122 ^'""'' 



nacula. It has been advanced that the heat of the wasp's occupation 

 may tend to " force " part of the brood, and after the autumnal 

 exodus of the wasps the remainder cannot at once attain maturity, 

 through the fall of temperature ; but I should require strong proof 

 before relying on so artificial an agency. Perhaps there is no fixed 

 time of emergence, as the following instances suggest. The duration 

 of the insect in the cocoon, at all events, appears by no means coinci- 

 dent with the pupal existence ; larva? have been found within the 

 cocoon as late as August 24th. We may, I think, grant that, usually, 

 the spring emergence produces that of the autumn, and that the cycle 

 is thus completed in about three months ; on the other hand, Bignell 

 records (Ent. Mo. Mag., xxvi, 191) a specimen received early in 

 September, 1889, which was still in the larval condition on June 6th 

 following ; and Stone (Zool., xx, 7974, and Proc. Ent. Soc, 1862, 77) 

 tells us that, upon himself opening cocoons, found in 1859, he released 

 quite mature and healthy imagines in March, 1862— after an incar- 

 ceration of three years ! He continues : " The moment the top of 

 the cocoon was removed, it marched out, stretched its legs, passed its 

 fore feet rapidly over its head and antenna?, for the purpose apparently 

 of removing any superfluous moisture "—this was extremely probably 

 the case, since the anterior tibia? are distinctly clothed on the inner 

 side with a short whitish villosity— "cleaned its abdomen, and smoothed 

 out its wings by means of its hinder feet, and was then prepared for 

 immediate flight. • • On opening the cocoons, a strong smell of 

 something akin to formic acid was emitted." 



Specimens of the spring emergence are fully winged and present 

 no conspicuous points of divergence from average Trypliones ; but the 

 examples of the later one possess but very short wings, and of use 

 only, like those of Agrothereutes, &c., in aiding propulsion by little 

 hops. Mr. Bignell's explanation, which is at least plausible, is that 

 the autumn emergence takes place in the wasp's nests, and the insects 

 consequently find the natural pabulum around them, and no need for 

 sustained flight exists, though that they are extremely vivacious, which 

 is, perhaps, necessary to avoid foreign attacks, Wood points out ; it is 

 doubtful, I think, however, if the wasps would molest them under 

 natural circumstances. The spring emergence, on the contrary, is 

 hatched in an empty nest, and must seek pastures new for the de- 

 position of its progeny. This theory is, moreover, borne out by the 

 fact that nearly all specimens taken abroad appertained to the spring 



emergence. 



Even this species, so appropriately called Clujrouomon by Des- 



