A STUDY OF THE GENUS MONOXIA — BLAKE 163 



and in having shallower elytral pimctation, and it differs from guttu- 

 lata m not having so long or so erect pubescence and not having a 

 marked depression on the elytra. The aedeagus, too, is more acutely 

 tipped. It resembles most closely M. debilis but is distinguished 

 from it (1) by the shape of the pro thorax, which is more rectangular 

 and depressed, and not so long as that of debilis, with only slightly 

 arcuate sides and with blunter basal tooth; (2) by having shallower, 

 denser elytral punctation; (3) by having longer pubescence, par- 

 ticularly noticeable on the prothorax. The aedeagus is not so heavy 

 as that of debilis and is more acutely pointed. As stated in the dis- 

 cussion of debilis, LeConte confused this species with obtusa (= debilis). 

 Both Cooley ^° and Essig '^ refer to a species of Monoxia injurious 

 to Cottonwood, but in all the collections examined, only a single 

 series, collected by A. N. Caudell at Denver, Colo., which closely 

 resembles this species and which consists of a larva, a pupa, and three 

 shriveled, immature adults, is labeled as being found on Cottonwood. 

 I have been unable to learn of any other collector who has observed 

 a Monoxia on cottonwood. 



MONOXIA GRISEA, new species 



Plate 19, Figure 15 



Large (about 4.5 mm.), broadly oblong, with dense gray pubescence; 

 elytra not depressed, coarsely but shallowly punctate; aedeagus longer 

 than that of M. debilis. Head covered with long, appressed, pale 

 pubescence hiding the punctation; lower front usually paler yellow 

 than occiput, labrum and median line dark, occasionally in dark 

 specimens head entirely dark. Prothorax not twice as broad as 

 long, with arcuate sides and well-developed but not conspicuous basal 

 tooth, disk depressed in middle and on sides; the coarse dense punc- 

 tation obscured by dense, closely appressed pubescence. Elytra 

 broadly oblong, coarsely but rather shallowly punctate, covered with 

 dense gray pubescence; often entirely pale and appearing grayish 

 from the pubescence ; in dark specimens elytra heavily mottled. Body 

 beneath densely pubescent; in pale specimens sometimes entirely 

 pale, in dark specimens dark except the last abdominal segments. 

 Legs pale or speckled. Length, 4.2 to 5 mm.; width, 2 to 2.2 mm. 



Type, male, and 4 paratypes (3 males, 1 female), U. S. N. M. No. 

 44020, collected in June 1904, collector unknown. 



Type locality. — Bozeman, Mont. 



Distribution. — Montana (Bozeman, Glendive, Gallatin County, 

 Musselshell, Shields River, Yellowstone River Valley); Idaho (Beaver 

 Canyon); Alberta (Medicine Hat, Edmonton). 



10 Montana Agr. Coll. Exp. Stat. Bull. 112, p. 60, 1918. 

 " Insects of western North America, p. 473, 1926. 



