307 



imtil I funud l>iirrows coutainiiig larvae. These were then 

 transferred Avith a brush into liypotlienemus burrows in a 

 short bit of a twig and this placed in short sections of glass 

 tnbe and this plugged up with cotton after placing a female 

 Cephalomomia with them. This is not such a simple matter, 

 since the female is only a millimeter long and the Hypothene- 

 mus is shorter though very much stouter. 



One of the females was unfortunately injured and was 

 mounted for preservation. Three females remained for breed- 

 ing purposes. 



After three or four days one of the twigs was opened and 

 two larvae were found bearing each a single egg on the venter, 

 and in about two weeks, from these a female bred out. This 

 female was so treated for five successive times and each exam- 

 ination revealed larvae of Hypothenemiis bearing one, two 

 or three eggs or larvae, according to circumstances, and a fair 

 share of these reached full growth and cocooned. The other 

 two females were less fruitful and only a single pupa bearing 

 a larva of the C eplialonomia on the dorsum of its abdomen was 

 obtained. One of them died without any egg laying. 



These trials revealed certain interesting facts : The egg 

 laying is slow; the females can live for considerable time with 

 only their host insects for food; usually adult Hypothememus 

 present in the twigs were dead or if living had lost their power 

 •of locomotion, the only signs of life being a slight twitching 

 movement of the legs. Further observation showed that when 

 pressed for food the C eplialonomia will feed upon the Hypo- 

 fJienemus pupa and adult as well as sucking the juices of tlie 

 larva. 



Having gone so far in the study of these s^iccics, I became 

 desirous of seeing how the minute Cephalonomia goes to work 

 in attacking its victims. I had found them not disposed to 

 work upon the larvae outside of the tunnels in the wood and 

 they did not easily become interested in larger Xylrhoni.^: larvae 

 ju williwili wood. 



At lenoth it occurred to me that thev micht work under 



