Two new Strepsipterous Insects. 45 



ultimate transition has been accomplished in some instances, — 

 the winged parasite having been produced as aforesaid within 

 twenty-four hours after the first indication of its presence between 

 the abdominal folds of the newly-developed bee, — would seem to 

 imply that the entire change, from larva to imago, can scarcely 

 be effected, as it were, per saltum, on such occasions. 



Among a number of other larvae and pupae of Hylceus, set 

 apart and carefully watched, I could discover no symptom of 

 Strepsipterous distension during either of those stages ; but at 

 length having noticed two pupae, extracted from a briar, on the 

 2nd of June, exhibiting on the right side only the dark markings 

 which usually precede the development of the bee, I found, on 

 their pupa-pellicles being discarded the next day, that Strepsip- 

 terous parasites, ready to burst forth, had become conspicuously 

 prominent on the opposite side, where their hitherto concealed 

 presence would seem to have had the effect of exhausting the 

 ordinary secretions within. I am also inclined to believe, upon 

 a comparison of numerous specimens of Hylceus, reared from the 

 briars, that the colour of the abdomen in the perfect bee was 

 often considerably affected by the abstraction of those substances 

 which had afforded sustenance to Strepsipterous intruders (parti- 

 cularly where the winged parasites were produced), as in the 

 pale-coloured specimens now exhibited. 



So long as the Hylcei remained in the dark, the parasites, de- 

 prived of those external influences which, under ordinary circum- 

 stances, would serve to stimulate their dormant energies, made 

 no attempt to abandon their pupa tenements ; as an incentive to 

 which, light appears to be absolutely essential, in order that their 

 perceptions may be awakened to an intuitive consciousness of the 

 bees having quitted their cells. Thus, as with those first obtained 

 from the oak-gall, some briars occupied by the larvae of the 

 Hylcei having remained shut up in a box, and the bees having 

 come to maturity and died unobserved, none of the parasitic skull- 

 caps were found to have been removed, — an operation which 

 seems attributable, therefore, to the unaided efforts of the para- 

 site from within ; so that, although fully prepared to quit their 

 pupa-cases, unless the parasites be aroused from their lethargic 

 stupor by the exhilarating influence of the solar rays, they termi- 

 nate their existence, together with the bee, without ever regaining 

 that liberty of action which at an earlier period they were privi- 

 leged to enjoy in their incipient hexapod larva form ; for, as Dr. 

 Siebold's careful investigations into the economy of the Strepsip- 

 lera have served to elicit, the little acariform beings so frequently 



