282 HENRY SHIMER, M. D. 



longest on tlie veins, apprcsscd on the membranes. Length of body 

 .03 — .05 inch. Alar expanse .08 — .10 inch. 



Larva on the surface of the leaves of Acer da.y/carpuni, Khrhart, 

 (White or Silver Maple), pale or whitish, the alimentary canal appears 

 through the translucent integument as a greenish stripe; often single 

 specimens on the leaf, more frequently in scattering groups of three'to 

 u dozen on the same leaf; the leaves become curled and irregularly 

 contorted, but there ai'e no galls; at length, after the maturity of the 

 insect, the leaves become dry and black. 



I have seen this insect in former years, but did not then study its 

 natural history. This year I first observed it on the Maple leaves, about 

 the 7th of July; they may still be fouiul, and have produced at least 

 three generations during this time ; from the 20th to 30th of July I ob- 

 served them most numerous, in all stages ; the cocoons are whitish and 

 are formed on the surface of the leaf, where the larva lived in some angle 

 of the contortions. The pupa seen through the cocoon is pale yellow- 

 ish, but the empty cocoon is quite white. 



That these pupa tenements are real spun cocoons, there no longer 

 remains a doubt, notwithstanding the opposite opinion of Entomologists 

 who jump to conclusions without observations, wishing to be consider- 

 ed masters of their business, and wise to perfection in Entomology.* 



I observed these cocoons in various stages of their construction ; some 

 just commencing, had thrown out stays in some angle of the crooked 

 leaf, precisely in the same manner as do the lepidopterous larvsie ; others 

 partially completed, still showed the strands of silk ; when entirely 

 complete they appear much like fine tissue paper. Is it not probable 

 that the whole web is cemented together with a gummy fiuid after be- 

 ing constructed, for the purpose of excluding water, and preventing 

 evaporation during dry weather, more especially the latter? On the 

 leaf of the tree, in midsummer, the insect is not so likely to be damaged 

 by excessive moisture as by excessive evaporation during the period of 

 its transformation. The silken threads of these cocoons are very fine, 

 but can be plainly seen with a good eye-glass of high power; the 

 thread was plainly seen also, by other eyes besides my own. With a 

 microscope the threads of the cocoon can be seen at the torn edges, as 



* Mr. Walsh's views on this matter are wild as well as amusing, and entirely 

 profitless; wherein he maintains (Proc. Ent. See. Vol. iii, No. 3,) that the co- 

 coon is extruded from the body of the larva, and afterwards inflated with gas 

 like a bubble. lie has been projjorly reviewed by Dr. Packard, (Proc. Eut. Soc. 

 Vol. vi; No. 2). 



