1036 



FAMILY LII. — CERAMBYCID2E. 



XXXI. Xylotrechus Chev. 1860. (Gr., "wood + a runner.") 



Medium-sized, slender species, having the front of head marked 

 with a carina or elevated ridge of variable form, which is best seen 

 by holding the insect with the front uppermost. In part of the spe- 

 cies the ridge is a smooth line starting below the eyes and running 

 a little past them, dividing at about the middle into two V or Y- 

 shaped lines diverging toward the sides of the head. In the re- 

 mainder of the species the diverging lines are absent, the division 

 being only represented by an impressed space. Six species may 

 occur in Indiana, though but three of them have as yet been taken. 



KEY TO INDIANA SPECIES OF XYLOTRECHUS. 



a. Frontal carina reduced to an elongate space. 



Z>. Carina scarcely divided ; black, shining, with narrow yellow margins. 



NITIDUS. 



Carina divided or impressed longitudinally. 



c, Thorax with four spots of yellowish pubescence; elytral markings 

 white, indistinct. 1916. quadrimaculatus. 



cc. Thorax marked with lines; elytral pubescence yellow, the lines 

 connected at suture. convergens. 

 aa. Frontal carina V- or Y-shaped. 



d. Elytra obliquely truncate at apex, the outer angle with a spine ; sides 

 of thorax regularly curved. sagittatus. 

 eld. Elytra obliquely truncate but without distinct spine at outer angle. 

 e. Thorax without apical and basal margin of paler pubescence ; ely- 

 tral bands about as broad as their intervals. 1917. colonus. 

 ee. Thorax with apical and basal margin of yellow or white pubes- 

 cence; median elytral band angulate or undulatory. 



1918. undulatus. 



X. nitidus Horn, length 12 mm., is known from New Jersey, 

 Pennsylvania, Ohio and Texas; X. convergens Lee, length 8-11 

 mm., is recorded from Ohio and Iowa; X. sagittatus Germ., brown- 

 ish with more or less white pubescence, length 15-18 mm., ranges 

 from Massachusetts to Arizona. 



1916 (6181). Xylotrechus quadrimaculatus Hald., Trans. Amer. Phil. 

 Soc, X, 1847, 41. 



Elongate, moderately robust, subcylindrical. Dull black; thorax with 

 a spot of yellowish pubescence in each angle ; elytra with the sutural line 

 and three oblique processes therefrom dull yellow and sparsely clothed with 

 whitish hairs; hind margins of meso- and metasterna and three or four 

 segments of abdomen also with transverse bands of whitish pubescence. 

 Thorax cylindrical, largest at middle ; surface with minute, irregular trans- 

 verse wrinkles. Elytra finely rugosely punctate on the sides. Length 12- 

 13 mm. 



Monroe County; rare. June 9. Taken from trunk of beech; 

 said to occur usually on the black alder. 



