227 



the infested wasps can always be detected by tlieir peculiar 

 zigzag or irregular flight. So remarkable is their appearance 

 in flying that I have detected them even when riding along 

 the road and have stopped and caught them among the bushes 

 by the way-side. After catching one of these infested wasps, 

 put it under a tumbler, and feed it with sugar, and in a few 

 clays or a week or two, you may have winged specimens of the 

 male Xenos in the tumbler. This insect is very impatient of 

 confinement, and keeps in almost perpetual flight till it seems 

 to die from exhaustion. The females never come out of the 

 wasps, and are not to be distinguished without close exami- 

 nation from the cased pupae or mature larvse. You will see the 

 black heads of the one or of the other just protruding from the 

 intersection of the dorsal rings of the abdomen. I have found 

 four specimens in one wasp. Two or three are common. 

 This is about all I can tell you of the insect from my own 

 observations. Some years ago I drew up a little paper on the 

 relations of the Strepsiptera, and came to the conclusion that, 

 from the structure and habits, as far as then known to me, they 



only five. " A larger bunch connected with the anal aperture" is not shown in the 

 drawing. 



These differences lead to the suspicion, either that Dr. LeConte has not correctly 

 described the larva or that the figure drawn by Mr. Clark represents another and 

 different insect. T. W. H. 



Since reading the above note I have reexamined the specimens of Psephenus larva;, 

 collected by me at Niagara, and find no reason to change the description published by 

 me in Agassiz' Lake Superior, except in regard to the branchice, which are five, as fig- 

 ured by Mr. Clark, instead of six as stated erroneously by me. The head is small but 

 prominent, and concealed under the shield-like pronotum and the membrane of the ar- 

 ticulation is distinctly visible. The appearance of a tendency to division in the joints 

 of the antennce is caused by a slight compression and twisting or rather by a faint ob- 

 lique impression. I may also add that the larva described was not the ' supposed ' but 

 the ascertained larva of Psepkenus (late Eurypalpus) since pupce, having the recogni- 

 zable form of the perfect insect were found under stones near the water, protected by the 

 shield-like epidermal extension of the larva. I have also examined the very nearly allied 

 larva of Hdlclius fastigiatus, and the remotely allied Stenelmis crenatus, in both of 

 which there is a hood-like prolongation or rather expansion of the pronotum; the last 

 named has however no external branchiae. [J. L. L.] 



