the Life History of Trocliilvmii midrenmforme. 473 



most Sesiids, does not prepare a spot in the mine from 

 which the imago emerges. The perfect insect on the 

 contrary, as ah'eady stated, emerges from the only hole in 

 the mine, from which the larval frass was also previously 

 ejected. Some of the specimens cover the opening over 

 with a cap consisting of a thin piece of bark quite separate 

 from the rest of the twig, which apparently remains on 

 until the insect emerges. The mine exhibiting this 

 peculiarity. Fig. 4, contained a living pupa which was 

 unfortunately cut through. Other mines lack the cap 

 and have the characteristic appearance shown in Fig. 2, 

 and in these cases the cap has obviously been dislodged. 

 Other mines, again, have an irregular piece of bark 

 gnawed right out, leaving the hole exposed, through 

 which the frass of the living larva protrudes. In such 

 cases as these one would imagine that the larva had failed 

 to make a cap. The construction of this cap appears to 

 us to be difficult of explanation, and it is hoped that some 

 other entomologist will solve the difficulty. One specimen 

 which we had in the breeding cage crawled out of the 

 twig, re-entered it, and bored a hole through the bark, 

 but not into the wood underneath it, and excavated a 

 circular spot between the bark and the wood in which it 

 lay concealed."'^- Figs. 5 and 6 represent mined twigs 

 from which ichneumons emerged. These have been 

 identified by Mr, Claude Morley as Menisctis agnatus, 

 Grav. Demo-pheles caliginosus, Grav., also identified by Mr. 

 Claude Morley, emerged from another mine. 



While the present article was in the press I found 

 several mines of this species at Tring, in Hertfordshire, 

 in Viburnuvi lantana, and one old mine (undoubtedly 

 belonging to this species) in Vihurnum oiyulus. 



* The mine of this specimen also contained the pnpa of a 

 Coleopteron. 



