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XXVIII. Entomological Notes. By J. O. Westwood, 

 M.A., F.L.S., Pres. Ent. Soc. 



[Bead October 3rd, 1877.] 



1. On the Pupa of a Trichopterous Insect. 



My young friend, Mr. Edward B. Poulton, B.A., of 

 Jesus College, recently brought me a pupa of a Trichop- 

 terous insect, which Mr. M'Lachlan considers to be that 

 oi Anaholia nervosa, one of the Limnephilides * which has 

 enabled me to correct certain passages in my Introduction 

 to the " Modern Classification of Insects," ii. pp. 68, 69. 



The mode in which insects having a quiescent or necro- 

 morphous pupa undergo their change to the perfect state 

 varies in the different orders. In the Lepidoptera, in 

 which the limbs are enclosed in separate sheaths and 

 fastened together by a gummy secretion on assuming the 

 pupa state, the legs are di'awn out of their sheaths, Avhich 

 remain fixed in their position along the breast, so that, 

 except for the slit down the back of the thorax, the cast 

 skin might often be mistaken for an entire pupa. In the 

 Diptera, Avhich undergo a coarctate metamorphosis, the 

 limbs are free, but the insect on shedding the outer skin 

 of the pupa has to burst by force through the indurated 

 shell formed of the last larval skin, whilst such Hymenop- 

 tera as are enclosed in the pupa state in closed cells or 

 cocoons have to burst through these coverings after as- 

 suming the -vvinged state. 



In the Coleoptera and most of the Hymenoptera, the 

 limbs are free although lying inactive along the breast ; 

 but immediately before assuming the imago state they 

 become endowed with a small amount of acti\'ity, and the 

 insect is able to creep or move about slightly, whilst still 

 entirely inclosed in its pupa skin. In certain Hymenop- 

 tera, the pupas of which are enclosed in cocoons of a hard 

 texture, such as the Cimbicides and other Tenihredlnidce, 



* The larva of this species, according to Mr, M'Lachlan, is fonnJ com- 

 monly in ditches and streams, with long twigs attached longitudinally to 

 the larva-case as balancers. 



TRANS. ENT. SOC. 1877. — PART IV. (dEC.) 



