Mr. W. B. Pickering on Strepsiptera. 163 



Fig. 10, The thorax and abdomen of the female seen from beneath, in the natural 

 position. 



Fig. 11. The extremity of the abdomen of the female seen from beneath distended. 



Fig. 12. One of the seventh pair of spiracles. 



Fig. 13. The extremity of the abdomen of the female seen laterally distended. 



Fig. 14. The dorsal portion of the three terminal abdominal segments of the female, 

 showing the relative length of the tracheae arising from the seventh ab- 

 dominal spiracle. 



XXXIV. Observations on the Economy of the Strepsiptera, 

 with the Description of Stylops Spencii, a new British 

 Species recently discovered. By W. B. Pickering, 

 Esq., M.E.S. 



[Read 5th January, 1835.] 



Of the value and necessity of recording observations which fall 

 under our notice, even should they merely relate to the most com- 

 mon insects, there can, I apprehend, be but one opinion, since so many 

 interesting particulars remain unknown in the economy of almost 

 every species, serving either as rewards for those who are willing to 

 search for them, or as the means of confirmation of what is already 

 known. If this be admitted in respect to well-known species, of how 

 much more importance is it that publicity should be given to facts 

 concerning those of remarkable structure and singular economy, 

 concerning which, although they may have excited the attention of 

 entomologists of all countries, we still remain, as regards many of 

 their more important features, in a state of uncertainty and doubt, 

 and where mere conjecture has endeavoured to supply many points 

 relative to their economy ! Of such insects perhaps the most re- 

 markable are the species composing the order Strepsiptera, and I 

 deem myself extremely fortunate in having made some recent obser- 

 vations on the genus Stylops which are likely to enable us (with 

 the help of future inquiry) to elucidate its history. Previous how- 

 ever to detailing these facts, I will cite the opinions of the different 

 authors who have written on this order as far as regards its natural 

 history. 



Rossi was the first entomologist to describe one of these remark- 

 able insects ; he was of opinion that the egg of the Xenos was de- 

 posited in the larva of the wasp previous to the closing of its cell ; 

 his words are : " Cui vespae larva antequam cellulse clauderentur 

 forte incunabula dedisse videtur." Our much-esteemed Honorary 



