1901 



ENTOMOLOGICAL SOCIETY. 



75 



by ribs and ridges. Within the coats of the egg are the yolk-mass and the germinal vesicle, 

 which lies within the yolk-mass. The amount of yolk-mass is usually large, and it is claimed 

 by Brauer that the egga of insects which undergo incomplete metamorphosis contain relatively 

 more yolk than those of insects with complete metamorphosis. As the germinal vesicle lies 

 within the yolk, it is securely protected against changes of temperature and moisture, as the 

 yolk is mainly composed of fat globules. The eggs of some insects possess remarkable vitality, 

 such as those of the " Walking Stick," and Bittacus, which survive two or more years. 



Naturally, then, we might expect to find some insects in all the Orders hibernating in the 

 egg state. The following common forms winter as eggs : — 



Plant-lice (Aphididae). 

 Tree-Hoopers (Membracidae). 

 Leaf-Hoppers (Jansidae). 

 Most Scale Insects (Coccidae). 

 Leaf-bugs (Capsidde). 

 Grass-hoppers (Acrididae). 

 Locusts (Locustidae). 

 Crickets {Grijllidae). 

 Walking-Sticks (Pltasmidae). 

 Gipsy Moths (Ocneruo dispar). 

 Fall Canker Worm (Palaeacrita pometarla). 

 Tussock Moth (Orgyia leucostigma). 



Tent-Caterpillars {Clisiocampa Americans, and C. disstria) 

 (fig. 33). ' • 



The Larvae. Insect larvae differ from the immature forms of other invertebrates in the 

 possession of the systems of organs and the same number of segments in the head, thoax, and 

 abdomen. When ready to pupate the larvae are always larger than the adults. 



Fig. 33. Egg-cluster of 

 Tent Caterpillar. 



Fjg. .36. Lachnosterna. 

 Grub " ; ?. and 4. Beetle, 



1. Pupa, 2. ' White 



Fig. 34. Cut- Worm. 



«aiC3XECCC£2:^ 



Fig. 35. Wire- Worms. 



From tlie fact that the larval stage is the growing time of the insect it is not to be expected 

 that hibernating larvae will often occur. Moreover, the relatively large amount of fluids within 

 the body of the larvre, and the thin dermis just after moulting, make them extremely sensitive 

 and liable to injury from freezing and other temperature changes. 



