—54— 



of the head is indicated in the annexed figure. There are two ocelH 

 on each side, very distinctly shown; the mandibles are very stout, 

 curved, with a broad gouge-like cutting face, somewhat irregularly 

 serrate or dentate, the opposing edges meeting accurately. The 

 maxilla is broad, fleshy, furnished with a double series of stout, 

 longer and shorter spines. The palpus is 3-jointed, the joints 

 smooth, short and stout. The labial palpi are 2-jointed, the basal 

 joint broad and flat, not visible, except on careful examination, the 

 terminal joint obtuse; the other features are scarcely characteristic 

 enough to describe, and the figure will give a good idea of the 

 mouth parts. 



HYPOTHENEMUS Westw. 



This genus deserves the careful study of a specialist, judging 

 from my observations made on the biological side of the matter. 

 From grape stems, infested by Phymatodes amoznus, I bred also a 

 series of Scolytids making perfectly straight, longitudinal galleries, 

 and occasionally boring a clean hole to the pith. Two-sized speci- 

 mens differing in form and vestiture were found, which I accepted 

 as male and female, and these Mr. Schwarz named as H. dissimih's 

 for the more robust form, and H. cruditus (large form, hispiduhis 

 Lee.) for the slighter form. I was convinced we had here the two 

 sexes of one species, but such occurrences in the Scolytids are not 

 rare, i. e. , where male and female are described as specifically dis- 

 tinct, and I thought nothing of it. All the galleries seemed made 

 by the imagos and I saw no trace of larvae. 



Some few days later, in cutting oak branches, I ran across a lot 

 of small twigs which had the centre hollowed out, and, rammed up 

 at one end, a line of beetles varying in number from three to six; 

 there were no larval galleries, and the infested twigs were only about 

 double the diameter of the inclosed beetles. There were here also 

 two sizes represented, and altogether they closely resembled the 

 grape species. I sent them to Mr. Schwarz, and in due time re- 

 ceived a return; the larger specimens, H. dissimilis; the smaller, 

 H. eredus. These two forms in oak I am also convinced are sexes 

 of one species, though what the exact relation of the eredus in oak 

 to the eriiditus {hispiduhis) of the grape may be I will not venture 

 to state. Unless polygamy exists among Scolytids I will not ven- 

 ture to guess why the males to both erudihis and erechis seemed to 

 be dissiynilis. 



About the same time I found, with Chra^iiesiis icoricc, in smaller 

 branches of the same trees a small species making a somewhat dis- 



