OF WASHINGTON. 393 



M. dent igertim "Lee. )iiercus agrifolia (J. J. Rivers 1. c.) 



M. mail Fitch Pyrus mains (Fitch 3d Kept. N. Y., p. 8), 

 Quercus, Negundo aceroides. 



Mr. Rivers's notes concerning the two California species reads 

 simply: ' Bark of dead Quercus agrifolia.'" From this it 

 might be inferred that specimens were cut from the bark, but 

 there can scarcely be a doubt that these species conform to the 

 known habits of the genus, and live in the solid wood of oak and 

 allied deciduous trees. 



Pityophthorus cariniceps Lee. is evidently a northern species 

 and thus far quite rare, having been taken by very few col 

 lectors. At Ithaca I found a single colony under the bark of 

 small twigs of white pine (Pinus strobus} August 21. A sol 

 itary specimen was taken on another occasion, also under white 

 pine bark, in October. Only one sex, supposed to be the male, 

 has been recognized, and the species has been previously recorded 

 from the single specimen, from which the description was drawn 

 (from Detroit, Mich.) and from Canada. 



Hypothenemus dissimilis Zimm . The typical form of what 

 there can be no doubt represents the two sexes of this species 

 were first taken by me at Ithaca in November, 1881. Eight spec 

 imens were found at one time, living in pairs, beyond question 

 male and female, and in another case six specimens were disclosed 

 in a single long straight gallery, all facing in one direction, 

 toward the blind end of the burrow, and tightly jammed in, in 

 perfect Indian file. Scolytidas are often found thus, and in 

 this instance had crawled together probably for warmth during 

 the cold weather, as is so often done by other insects. The 

 gallery from which these six specimens were taken had three 

 branches, representing as many pairs of the insect. In all cases 

 observed by me the beetles were found in one end of the stem and 

 near the joint, at which point they extend their burrows trans 

 versely and irregularly. From the joints other burrows ran in 

 straight lines through the pith and parallel with the stem. As 

 previously intimated, this species appears to live habitually in 

 couples, but often in company with other grape-stem borers, e. 

 g., Phymatodes amcenus and Lyctus opaculus, all three species 

 having been taken from a stem only an inch and a quarter in 

 length. The specimens found were all adults, neither larvae nor 

 pupas being present, although the larvas only of the associated 

 species were present in the canes at this time. 



In my small series the larger specimens, the supposed females, 

 are all of uniform size and general appearance. Those which I 

 take to be the males are also uniform in size and appearance, but 

 nearly a third smaller. The abdomen is proportionately shorter 

 and the thorax broader than the elytra. In the supposed females 

 the thorax and elytra are of equal breadth ; the front margin of 



