252 



PSYCHE. 



[September, igoi 



WILLEM ON APTERYGOTA. 



The recent memoir, Reclierckes sur les Col- 

 lemboles ct Ics T/iysanoiires (Brussels, 1900) 

 by Victor Willem, is a work of exceptional 

 importance. It gives an abundanll3- illus- 

 trated account of the anatomy of the princi- 

 pal genera of Collembola, supplemented by 

 valuable morphological and phylogenetic dis- 

 cussions upon Apterygota. 



The author sustains the view that the ecto- 

 gnathous forms are the more primitive. 

 Willem agrees with Fernald that the ventral 

 tube is supplied with an adhesive fluid by a 

 pair of cephalic glands and defends this in- 

 terpretation. The lateral eyes of most Col- 

 lembola are shown to be, not ocelli, bui en- 

 cone constituents of aggregate eyes ; in cer- 

 tain Poduridae, however, the eyes are simple 

 ocelli. Grenacher's theory of the ocellar 

 derivation of compound eyes receives strong 

 support. The postantennal organs are per- 

 haps olfactory in function. Abdominal ap- 

 pendages of Thysanura are regarded as mod- 

 ified limbs. The fat body is hypodermal and 

 doubtless excretory among Collembola. Wil- 

 lem gives critical observations upon ovo- 

 genesis and spermatogenesis. 



In style, the memoir is refreshingly concise 

 and clear, — so consistently concise, in fact, 

 that the criticisms upon other works are 

 often more abrupt than elegant. Although 

 the seventeen plates are left to tell their own 

 story as far as possible, the wprk is a mine 

 of new information and is indispensable to 

 future students of the Apterygota. 



The Royal Academy of Belgium awarded 

 Willem six hundred francs for this deserving 



THE INNER COCOON OF ATTACINE 

 MOTHS. 



BY CAROLINE G. SOULE. 



Proiiict/icii, attgulifeya, gloveri, ceaiio/lii, 

 and cccropia spin the mouth of the inner 

 cocoon in the same way. On pulling off the 

 outer cocoon the inner one is found to be an 

 oval bag, firm and tough, with one end 

 "gathered," like any bag shut by pulling a 

 draw-string, but in the cocoon there is no 

 drawstring. The gathers, or puckers, are 

 not quite regular, but they bring the edge of 

 the cocoon to a central point, closing it as 

 much as is necessary to protect the pupa. 

 When the moth is ready to emerge it has only 

 to push through this end of the cocoon when 

 the "gathers'" spread out and exit is easy 

 without any dissolving fluid or cocoon- 

 cutters. 



How the caterpillar gathers the end of the 

 cocoon I have not been able to discover, nor 

 can I see what holds the gathers in place at 

 the same time allowing them to spread out 

 when necessary. Of course the pressure of 

 the moth spreads them, but how were they 

 made to draw together, and what trick of 

 spinning held them together without making 

 them immovable? 



However done it is a beautiful bit of work, 

 and gives the Attacinae the easiest possible 

 exit from their cocoons. 



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