20 Observations upon Trochilium crabroniformis, 



of larva. There are others, on the contrary, which are more 

 frequently met with in the larva than in the perfect state; 

 e. g. Smerinthus populi (poplar hawk), Cerura vinula (puss 

 moth), Episema cseruleocephala (figure of 8), Clisiocampa 

 Neustria (lackey), Eriogaster lanestris (small egger), Odonestis 

 potatoria (drinker), Mamestra pisi (broom), &c. I do not 

 say that all these are rare in the winged state, but merely that 

 they are far more frequently met with in the state of cater- 

 pillars. Possibly, many may be devoured by birds, or preyed 

 on by parasitic Hymenoptera, and so do not come to per- 

 fection ; but I think that their comparative infrequency in the 

 winged state arises chiefly from their habits. A person may 

 walk through a wood which abounds with the little brilliant 

 purple hairstreak (Thecla quercus), and yet not see a single 

 individual, unless his attention is directed to the right quarter. 

 These insects keep hovering about, and settling upon the sum- 

 mits of oak trees ; in which situation they sometimes absolutely 

 swarm. They rarely approach the ground ; and, even in a 

 cloudy day, if disturbed by your shaking the trees, they 

 settle again in the same place. This insect then, though com- 

 mon and abundant, is not obvious. 



But I am straying sadly from the particular subject which 

 suggested these remarks ; viz. Trochilium crabroniformis. 

 (Jig* 3 T fte larva of this insect feeds upon the living wood 



tllJ HI 



a, Female, b, Male. 



of the broad-leaved willow (Salixcaprea), the stems of which 

 it perforates, entering them near the root, and eating its way 

 upwards for several inches, sometimes to the length of a foot 

 or more {Jig- 4. c). # (See the specimens sent: Jig, 5.) 



* See Transactions ofLinncean Society, vol. iii. tab. i., for a figure of the 

 insect in its three stages [from which our figures are copied]. Lewin, the 

 writer of the article, gives it as his opinion that " the caterpillar does not 

 enter the wood till the second year of its own age ,• " and he states as a 

 reason, that, " among all the numerous larvae he has found from June to 



