106 THE ENTOMOLOGIST. 



and the colour of the legs, etc. ; also the cocoons are particularly 

 dissimilar. From D. marginatus it differs in having the meta- 

 thorax and first abdominal segment much smoother, etc. 



Cocoon smooth, thick, dark chocolate brown in colour, pointed 

 and wrinkled from end to end, though occasionally this last 

 character is scarcely noticeable. 



The larva is dirty yellowish white, with the divisions between 

 the segments appearing darker, minutely punctate, parts of the 

 mouth outlined in brown ; length, 4j mm. It emerges from 

 the centre of the dorsal surface of the host where the cocoon is 

 constructed in an upright position and firmly fixed to the body 

 of the caterpillar (Fig. 1). The unfortunate host lives for several 

 days after the emergence of the parasite larva, and carries its 

 strange howdah about so long as power of motion is retained, 

 and even death does not sever the connection. I have obtained, 

 perhaps, twenty of these cocoons at various times, but have 

 never known the imagines to emerge naturally therefrom. 

 When I have cut open the cocoons, some twelve months after 

 their construction, I have invariably found the imagines to be 

 perfectly developed but quite dried up, having evidently been 

 dead some time. It can scarcely be through lack of moisture 

 that the insects have failed to emerge, as I have tried keeping 

 the cocoons on damp sand during the winter. A suggestion has 

 been made to me that a different result might have been obtained 

 had I allowed the cocoons to remain attached to the dead bodies 

 of the hosts. Up to the present, however, no o[)portunity of 

 testing this has occurred. Always a solitary parasite, I have 

 once obtained it, somewhat doubtfully, from a larva of I>rephos 

 parthenias, and many times from larvae of Lohojiliora carpinata. 

 Twice I have bred the hyperparasite Astiphronimus plagiatus, and 

 once (July, 1910) Mesocliorus confusus, these int-ects apparently 

 having had no difficulty in gnawing their way through the hard 

 cocoons. 



Genus 5.— Microgast.er, Latreille. 

 This genus was formerly co-extensive with the family, but 

 has been at various times denuded and will bear still further 

 dismemberment, for, as Marshall very correctly observes (' Trans. 

 Entom. Soc.,' 1885, p. 238), it contains some of " the largest and 

 most typical forms (Marshall's, Section 1) artificially associated, 

 in consequence of the completeness of the second cubital areolet, 

 with an inferior group (Section 2) which might even be made a 

 separate genus with as much pro{)riety as Apanteles.'' Mar- 

 shall's two groups are very distinct, and it is to be regretted that 

 Thomson did not extend his genus Hygroplitis to cover all the 

 species in Section 1, for it seems an anomaly that such a species, 

 for instance, as M. tibialis, though placed in a different genus to 

 the nearly related Hijgroplitis rtigulosns, should be associated 



