1890.] President's Address. xxix 



It would take me too long to enumerate all the series of parasites 

 and their habits, to tell you of the Scolia who, instead of carrying her 

 capture to the nest, digs her way to the larva of Scarabceid, and after 

 the usual paralysing process fixes her egg on the fat grub ; of the 

 Crabro 9 who makes use of hollow twigs for heaping in her supply of 

 flies, of Mutilla, and of so many others ; but I must call your attention 

 to the very singular insect shown in this diagram. 



It is one of the Strepsicera, a Stylops. It is a parasite which attacks 

 at random any Hymenopteron. I have found it on Apidae on Vcspidae, 

 on Pompilidae ; it has been found also on Formicidae. But if 1 

 mention Stylops it is because that unfortunate Odyuerus, I have so 

 often spoken o^, teems with them. 



The difference between the male and the female is very striking. 

 He has very large protruding eyes and long postical wings ; she is an 

 eyeless, legless sack. He leads the life of other insects ; she lives and 

 dies where she has affixed herself. She is provided with a dorsal tube, 

 from which her young will exude, because she is viviparous. 



The larva, provided with legs and two long caudal appendages, 

 clings to the hairs of the bee, and is carried by its mother's host into 

 the nest. It bores its way into the grub, and then changes into a leg- 

 less, maggot-like creature, which becomes a pupa into the hymenopteran 

 pupa, and taking advantage of the then moist state of the ultimate 

 transformation of the bee bores its way from the abdomen. If it is a 

 female, she will stay there until she dies ; if it is a male it will leave 

 the pupal skin and search the female. These insects do not, however, 

 devour the host, which completes its metamorphosis. 



What deduction must we now draw from the habits of these solitary 

 Hymenoptera, which form the subject of my address ? ' 



Must we consider them as endowed with superior intelligence ? Is 

 their instinct limited ? 



We must not forget that the young has had no lesson from the 

 mother. She has grown solitary ; the moment she has reached her 

 adult state, she has repeated unconsciously the same acts that her 

 mother had accomplished, unknown to her ; or, in the case of the male, 

 what his father had done. All her powers of intelligence have been 

 directed to ensuring the future life of her grub ; but while admiring 

 her intelligence in many of her doings, some of her actions reveal a 

 very obtuse mind. 



The Ichneumon is unable to discern befDre she is going to puncture 

 her victim if the place has not been occupied before by another 

 Ichneumon ; or if the larva of the Curculio has not reached such a 

 state of growth, that her young runs the risk of being entombed in tl)6 

 cocoon of the host before it has completed its metamorphosis. 



Odyne?'us takes no notice of the ruby-tailed flies which are actually 



