june · 2019. 8. 1. · 28 [march i888 deeply suttused with red; in this state they can be found...

PYCHE.

MIMICRY IN HEMIPTERA.

E. P. VAN DUZEE, BUFFALO, N. Y.

The family lygaeidae presents uswith two examples of protective mim-icry that seem well worth recording.These cases which are very similar,have doubtless been frequently observedby collectors, but I have seen no pub-lished account of them. I refer to theadolescent stages of Cymus angusta-tus and Oedancala dorsalis ; both liveon the various species of Carex anduncus growirrg in swampy pIaces inopen woods and pastures.

Cymus angustatus occurs princi-paily on uncus nodosus and allied spe-cies, but is frequently found on thesmaIler Carices; it is extremely abun-dant in the Iocalities mentioned above,and along roadside ditches, and in factwherever the uncus grows. In thisvicinity it appears in May, and continuesuntil late in autumn; copulation takesplace about the first of July, the imma-ture insects are abundant through thelast of July, the imago appearing fromthe first to the tenth of August. Theyoung, at least in the nymph state, beara striking resemblance to the capsulesand perigynia of the plants on whichthey occur; they are of a dull straw-

color, ovate in form, compressed orsomewhat lenticulate, acute behind,produced and blunt before, and withthe connexivum expanded and very thin.When taken in the sweep-netwith theglumes and fruit of these pl.ants, it isall but impossible to detect them as longas they remain quiet, which however,fortunately for the collector, is never forany considerable length of time. Ihave frequently poked them aside withmy tweezers, never suspecting their truecharacter until they indicated it byscrambling to their feet and runningoff, which they did with surprisingfacility.

Oedancala dorsaNs is a larger spe-cies and rather less abundant; it occurswherever Carex vulflinoidea can befound, but can frequently be taken onother species of Carex and Cyerus.In the nymph state it greatly resemblesthe preceeding, but is larger, morerounded in form, has a conspicuousdark line on the dorsum, and is of amuch more sluggish disposition; it isequally difficult to detect, when on theplant or mixed with the contents of thesweep-net. The imago when senile is

28 [March I888

deeply sutTused with red; in this statethey can be found through June andJuly, when, however, they are lesscommon than at other times: theyreach maturity about the tenth of _A_ug-ust, but occur throughout the summerfrom May to September, being the mostabundant in A.ugust.

I would here mention another hem-ipteron that affects the same plants,through July and August, the Liaurniadorsalis of Fitch, who described it

under the Fabrician genus Delphax.Like the foregoing species it derivesprotection by its close resemblance tothe inflorescence of its native grasses,being of a soiled yellow or testaceouscolor with a darker dorsal stripe. It isnot a common species here, and is dif-ficult to capture as it is very shy andagile, and when approached leaps soquickly that the eye cannot follow it.I have never taken the young.

VARIABLE NUMBER OF MOLTS OF INSECTS.

BY ANNA KATHERINA DIMMOCK, CAMBRIDGE, MASS.

The first notes given below are trans-lated from a paper by Alfred Wailly,entitled "Educations d’attaciens srici-gines faites g Norbiton, Surrey, Angle-terre, en 884" (Bull. d’insectol, agri-cole, Nov. 885, v. o, p. 73"74)""In nay English article, recently pub-

lished in the Journal of the Society ofarts, of London, I have given certainaccounts of the curious system employedby Mr. Weniger in rearing lepldopteraand ofthe extraordinary results obtainedby him. He rears the larvae in a largeglass box,.a green-house in miniature,heated.by a kerosetae lamp, upon whichis placed a saucer filled with water.The larvae, kept at a uniform tempera-ture of about 25 degrees centigrade, livein an atmosphere charged with thevapors of water and kerosene, and in-

stead of dying of disease, they developwith extraordinary rapidity. I haveseen the larvae of Antheraea mylilla,hatched seven days after the depositionof the eggs, arriving at their last stagetowards the end of a month. Attacusatlas was reared in a like manner, andfourteen days after the formation of thecocoons, the emergence of the mothstook place; but not a single copulationwas obtained. Many delicate speciesdifficult to rear, have been reared inthis manner with great success."There is also a fact which, I think,

here merits attention. The larvae ofAntheraea mylitta and of Ceratocam2baimperialis, species considered, as hav-ing six stages, and which, when rearedunder normal conditions actually havethe six stages, when reared in this

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june · 2019. 8. 1. · 28 [march i888 deeply suttused with red; in this state they can be found...

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