ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



645 



filled with transparent, highly refractive fluid. " The slightest injury 

 gave rise to the escape of the fluid, and left the spindles in a shrivelled 

 condition, the usual appearance of these bodies." Further investi- 

 gations have shown that all compound eyes, when uninjured, have 

 similar ovoid spindles ; these appear to act as magnifying and erecting 

 lenses. 



Four distinct modifications of the cornea have been observed ; 

 simple continuous, facetted, histoid, and lenticular. It has been found 

 that, during the process of ecdysis, the segregate retina of many larvae 

 is finally replaced by a newly formed retina, which is continuous ; it 

 would seem, therefore, that a kind of internal ecdysis affects the 

 epithelial elements of the nervous system concurrently with the 

 general integumental ecdysis. 



Results of Decapitation in Insects and Myriopoda.* — Taking 

 advantage of the large numbers of insects driven out of their hiding 

 places by the last autumn's floods in Italy, E. Canestrini carried out 

 some experiments in this direction, in order to ascertain how long 

 movements would continue in the heads and bodies. He commonly 

 employed very thin-bladed forceps for the purpose, and had recourse 

 to artificial irritation when spontaneous movements ceased (e. g. 

 pricking, squeezing, blowing tobacco smoke over the insect). Coleoptera, 

 he finds, at once showed signs of having undergone a serious operation. 

 Many of the more active Hymenoptera and Orihoptera, as the ants, bees, 

 Bomhus, Harpalus, &c., remained as if unaffected, while others seemed 

 only to recover their senses long after the operation ; Lepidoptera do 

 not seem much discomposed, and Diptera (horse-flies, house-flies) 

 show even less annoyance. Indeed several female flies which had been 

 decapitated coupled with uninjured males directly after the operation 

 and remained in this condition for 1 to 2^ hours and made movements 

 indicative of no great discomfort afterwards ; in one case the female 

 coupled twice during the 9 hours following decapitation. 



Statistical tables show the duration of movements in the following 

 (among other) insects to be as follows : — 



Body. 



Geotrupes stercorarius .. 5 days 



Cetonia aurata 9^ „ 



Harpalus 60 hours 



Various Butterflies .. .. 18 days 



Formica rufa 30 hours 



Wasps 5 days 



Flies 36 hours 



Forjicula 11 days 



Gryllotalpa 9 days 



Head. 

 16 hours 



4 

 10 

 few 

 30 

 24 



6 



6 

 78 



Most of the results were obtained at a temperature of 10° C. The 

 duration appears to be imaffected by the exudation or retention of 

 liquid at the wound ; a temperature as low as 5° to 10° C. is favoui-- 

 able to it, a hot, dry atmosphere soon renders the parts stiff and 



Bull. Soc. Venet.-Trent. Sci. Nat., ii. (1883) pp. 119-25. 



