THE COTTONWOOD LEAF-BEETLE. 



427 



6. Dorytomns mucidus Say. 



This insect is found running on and flying about cottonwood trees 

 early in April and again in August. In October it is found under 

 dead bark of trees in winter quarters. Common. Illinois. (A. S. 

 McBride. Can. Ent., xii, p. 106.) 



7. Eros coccinatus Say. 



Found in April in Illinois in the cottonwood, under logs in the woods. 

 (McBride, loc. cit.) 



8. Wallastonia quercicola (Boheman). 



This was taken by Mr. W. Knaus from " cottonwood logs in a some- 

 what advanced state of decay." 



The beetle appears in Kansas in June and July. " The present 

 season I took about a dozen specimens from logs that had been used in 

 a stable for the past seventeen years ; a number were taken from the 

 larval burrows, and numbers of small white fleshy larv.ne were also 

 observed in the same pieces of timber; these larvse, I feel confident, 

 were those of W. quercicola, but as I found no pupae and did not con- 

 tinue my observations on their transformation, I can not speak with 

 absolute certainty." He was strengthened in the conviction that the 

 arvae of this weevil are wood-eating by the fact that it has a close 

 structural relation to the Scolytidse. (Bulletin Brooklyn Ent. Soc. vii, 

 p. 150.) 



9. Mecas inornata (Say). 



Mr. Walsh has described the excresence made by this borer in the 

 saplings of the cottonwood and willow in Illinois. 



A rather sudden swelliug on such of the main stems as are .50 to 1.25 inch in diame- 

 ter, cracking open in two or three deep, irregular scabrous, brown, more or less trans- 

 verse, gaping, thick-lipped fissures. This is the appearance i)resented as early as 

 August and until the following spring; but July 19 nothing is seen but a smooth, 

 elongate swelling of the stem, pithy inside, and without 

 any cracks or roughness outside, and undistinguishable 

 externally from the tenthredinidous gall, aS". nodus n. sp., 

 in the form in which it occurs on the same willow later in 

 the season. Very probably, however, as with many if not 

 all Saperdw, the larva is at least two seasons in arriving at 

 maturity, and the normal appearance of the pseudo-gall is 

 not assumed until the following season. The insect does 

 not make its way out in spring through the deep cracks of 

 this pseudo-gall, but each bores a hole for himself in the 

 manner usual in this family. The gall on the cottonwood 

 is absolutely identical with the willow-gall, and was recog- 

 nized by myself as such at the first glance. It was found 

 exclusively on young saplings. In both cases it was per- 

 fectly healthy plants that were attacked. Although this 

 pseudo-gall weakens mechanically the stem upon which it 

 grows, and to such an extent that it occasionally causes 

 the stem to break in two with the wind, yet otherwise the 

 stem never perishes, but on the contrary the wound is gradually healed and over- 

 gro\yn by fresh woody matter (Walsh). 



Fig. 156.— Mecas inornata.-^ 

 Smith del. 



