dorsal...thelarva transforms in ten days and is, when fully grown, 44 mm.long. as it approaches...

32"2 PS’CttF.

INTERNAL ORGANIZATION OF HESPER[A ETItL1U;. CRAM., ASOBSERVED IN THE LIVING ANIMAI.

I’,Y ItILEN SELINA KING, SAN ANTONI(}+ TEXAS.

Wih edi/.orial auolatios.

Tnz larva of tIesperia ethlius may befbund on the Canna or Indian-shot plant.This larva being somewhat diaphanous,and thus affoing facilities fo all ex-amination of its internal organization,I have made o[’ it careful study.The egg, when firs laid on a lea/; is

pinkish, smooth, 1)iscuit-shaped, andwith a central depression on its upper,convex side. As it matures it growswhite. The larva emerges in six days,and eats up the upper third of its shell,which is detached like a lid, leaving a

cup still adhering to the plant. At thistime it is 1.6 ram. long, (lull whitisl;head very large, black, glossy, and bi-h)bed. True feet and anal tip black.I a few hours it sheds its skin.

[laving eaten tt small portion of the leaf;and thus prepared a section of it for itsuse, the larva folds this over and confinesit to its place with t few stitches of silk,enlarging this temporary retreat, or

/blding a new section as it grows andjust before the pupal change lining itwith silk. It feeds from this tubularcase, just along its edges, retreatingwithin when alarmed. It forcibly ejectsall excrement from the upper, free end,together with all exuviae, so that, al-though it evidently sheds its skin severaltimes these cast skins cannot be ibud.The larva increases more rapidly in

size at its early stage tlmn later, anddoubles its length i, 24 hours. It iscylindrical flattened o the veter and

presents rather a large upper sin’/he(,.At this time a transverse band is seenon dorsum of the lth segment, con-necting the posterior pair of stigmatawhich are faintly visible. Under a mi-croscope of 75 diameters may also beseen the dorsal vessel lying over andcontiguous to the alimentary canal, anda pair of small bodies between these andthe pleura, situated in the 9h segment,on each side [testes in , ovaries inWith its further development the body

becomes more opaque, from the 1)resenceof bod iu the alimentary canal. Wleit is 6 ram. long the small organs in tle9th segment are well defined, being four-chambered, with the divisionsthe extreme ones terminating sometimes[in the 9 ] in an acute point, the ante-,’for one longest. These vessels areabout the size ro,d of a 1)room-strawand about twice a lo,g as wide; of apale yellow, and ol)aque.

Lying over the alimentary canal, andseemingly formed of a fold of it avethe two longiudial tubular bodics alittle flattened wlich are interrupted butnot obliterated at the intersection of tlesegments dorsal vessel, with its valves].This tubular fold seems to recedeand approa(:h the median linv each timeapparently opening and ch)sing on thel)osterior half of its length for the ad-mission of fluid. There is a vevmicularmotion throughout these parts, butofluidcan actually be seen fi()wing through them.

PSUCItE. 323

The larva transforms in ten days andis, when fully grown, 44 mm. long. Asit approaches maturity the four-cham-bered vessels [ovaries] become cylindri-cal, and twice their original length, andwith points on the lower sides from tile

constricted parts. Tile riffler develop-ment of the alimentary canal and the

longitudinal tubular fold [_dorsal vessel]causes these smaller vessels [owries]to recede more from the dorsal median

line and approach nearer to the pleurain the comparatively free space occupiedonly by the ramifications of thecheae, tIere they seem to be balanced

upon and permeated by fine tracheaefrom the spiracle of the 9th segment, and

move synchronously with tile geeralimpulse received through the series of

spiracles on the pleura, but begun in the

pair on the llth segment. This pairof spiracles, connected by a short trans-

verse band or spiracnlar tube, gives rise

to two sets of tracheae: one penetratingno /rther than into the subcutaneous

enveloping membrane, ramifies there,giving no signs of activity; the otherresponds to, if it does not originate,every impulse of the larva.Each of the spiracles has a similar

double set of tracheae acting in thesame way. Tile air tubes of the passiveset just referred to, are inclined a littlebackward, transversely at their freeends, while those of the active set, ram-

ii’ing within the inner parts of the body,tend forward A part of them, neetino"on the middle of the venter, arch over a

small, misty, suboval dot [nervous gttu-

glion] which las a tint sympatheticmovement with the tracheae touching it.

One of these misty, white bodies issituated on each segment: beginning,from behind, at the 10th, where it seemsto be a double, oval dot, and is presuma-bly composed of the ganglion bf thellth and 10th. The next four anteriorto this are single. The fifth and fourthare near each other and nearer the 3rdsegment, showing a forward tendency.Each of the three thoracic segments hasits separate ganglion, equidistant fromeach other, and nearer together than theseries posterior to them. Each of theseganglionic nuclei is situated in the ante-riot angle of a triangle of white filamentswhose btse line is almost sraight acrossthe segment.On the dorsum and ending on the ren-

ter are long tubes (malpighian vessels)one on ech side, first traceabl near the10th spiracle, with which they are con-netted by a bent tubular line. Follow-ing t direct course forward from this asflu" as the (;th, those tubes recurve andreturn to the 9th, going tbrward oncemore at an acute ngle and losing them-selves in the 5th, but becoming againvisible just below the third segment.These tubes re of the same size and al>-:gearance as tle tracheae, with which theycome in frequent contact. At the pos-terior end of the tlfird segment, a.re theblunt eds of a pair of tubes [silk ves-

selsJ. These may be fifintly tracedalmost t<> their position <>n the hea(l asthv spimeretf.At times when the larva is ,mdisturbed

there seems to be an almost total suspen-sion of m<>tion in the spiracles and in allthe parts affected by them. With the en-trance of air into the system of spiracles

324

there is a regular pulsating movement inthe dorsal vessel, and in the small four-chambered bodies in the 9th segmentovaries]. The entrance of air into theposterior pair of spiracles seems to givethe initial impulse which travels so rap-idly along the series and its ramificationsthat almost immediately the head of theinsect begins to move fiom side to sideas if affected by the same influenceswhich afflicted the other parts. This oc-curs when the leat)- covering of the lar-va is cut open and light and air admitted.The first conscious effort of the larva

when its sheath [nest] is opened is di-rected toward the elaboration of silkfluid with which to enclose itself oncemore within its case. With this purposeit eats rapidly and the silk fluid is seenat the same time accumulating in andnear the thoracic segments. The larvauses its short, black, front pair of ibet tounite the threads which it spins back

and forth, %rming a cord of 50 to 75threads, as may suit its purposes.The pupa exhibits no specially inter-

esting features. It is pale green, withfaint traces of the outer set of tracheaestill visible; broad at anterior end, witha sharp black spine from its extremity,by which it is attached to a mass of finewhite silk. Body cylindrical, taperingat anal end. A loose girdle of silk pas-ses around its body, and its entire lengthrests against a delicate layer of whitesilk. If disturbed it moves with greatrapidity. It transbrms in ten days.The motions of the imago of this hespe-perian are very rapid.

I have not sufficient data t make thisan exhaustive monograph, but other stu-dents may have added what I have omit-ted. If not, we may leave to time anddiligence the fiwther discovery of suchfacts as are yet nknown.

CIRC[LATI()N ()F BLO01) 1N THE LARVA ()F HYDROPHII.US.

BY GEORGE I)IMMOCK, (AMBRll)GE, MASS.

EXAMINATION Of living larvae of Hy-drophilus under the microscope, the pastsummer, revealed the circulation ofblood in their antennae and trophi, whichis so distinctly visible and so curious inits directions as to be worthy of notice.The blood of the larva of Hydrophilus,

after leaving the anterior extremity ofthe dorsal vessel or heart and enteringthe head, divides itself into two lateralbranches, one of which descends oneach side of the oesophagus, the twobranches reuniting beneath the oesoph-agus, a little anterior to their divisionon its upper side, to form a median

stream. Between the point where thestreams separate and reunite, eachstream gives off three branches, all ofwhich flow in the same direction as themiddle stream formed 1)y the reunionof the two lateral streams, that is, tow-ard the anterior part of the head. Themedian stream formed by the reufion ofthe two 1,’tteral streams, which is, ofcourse, more ventral in position than thesix other streams, enters the middle ofthe labium, and passes along the dorsalhalf of that organ until it nearly reachesthe bases of the labial palpi. Here thestream turns ba(.k laterally anal ventrally,

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