Predaccous Insects and their Prey. 365 
foes of the Ichnewmonide.* The other insect prey is very 
varied : a Bracon ?, a Tenthredinid, two flies, (a Syrphid 
and an Empid), a Panorpa and a small moth. Further 
material is greatly needed in order to test the provisional 
conclusions here arrived at, and to afford grounds for 
estimating the relative influence of the various species 
of the genus. 
Dasypogon (Selidopogon) diadema, Nos. 11—55.—The 
record in the case of this species is remarkably complete, 
no less than 45 examples being tabulated. Of these all 
except one, in which the nature of the prey is uncertain, 
are available for an analysis which demonstrates at a 
glance the relative preferences of this predaceous species. 
The Prey of Dasypogon (Selidopogon) diadema. 
HEMIPTERA. 
Coreide. : : : : : 1 
Toran ae! 
COLEOPTERA. 
Hydrophilide : : : : : Sa 
Copridx : ; ‘ : : ie 
Glaphyridex ‘ : : : ee 
Cetonunde . : ; : . (abandoned) 1 
TOTAL . ; SOG 
* That the Hymenoptera are the special victims of Dioctria was 
well known to Kirby and Spence. Thus we read (Fifth edn. 1828, 
vol. i, p. 274) :—** The Asili also, which are always upon the chase, 
seize insects with their anterior legs and suck them with their haus- 
tellum. The cognate genus Dioctria, particularly D.iclandica, prey 
upon Hymenoptera, by some unknown means instantaneously killing 
the insect they seize.” 
This last observation is also of great interest. The collapse of the 
Asilid’s victim—often an active powerful insect—is so instantaneous 
that there can be little doubt that a poison is injected. In the case 
of Laphria gibbosa (No. 86) which was devouring the Buprestid 
beetle Ancylocheira flavomaculata (see p. 339) the proboscis was thrust 
through the cephalo-thoracic articulation. Dr.Chapman has pointed 
out to me that if the beetle had not been already killed or killed 
the instant of insertion it could have crushed the Asilid’s proboscis 
with ease. When an Asilid is captured and held by the wings it 
often extrudes asif in defence a frothy liquid from the end of its 
proboscis ; and it is probable that this is the poison. It would be 
interesting to experiment upon insects with it, introducing a minute 
quantity by means of a finely drawn out glass tube. 
