74 



THE SCOLYTID BEETLES. 



No. 6. THE SMALLER MEXICAN PINE BEETLE. 



(Dendroctonus mexicanus Hopk. Figs. 35, 36.) 



The smaller Mexican pine beetle (Hg. 35) is a dark brown, elongate, 

 cylindrical barkbeetle, ranging in length from 3 to 4 mm., with head 



broad and grooved, prothorax 

 but slightly narrowed toward 

 the head, and punctured, and 

 elytra with coarse rugosities 

 toward the base and declivity, 

 the latter with long hairs. It 

 attacks pine trees in Mexico, 

 where a large amount of timber 

 has died in certain localities, evi- 

 dently owing to the work of this 

 and the larger Mexican pine bee- 

 tle. It excavates winding egg 

 galleries (fig. 35) through the in- 

 ner bark, the larval mines being 

 concealed, like those of the west- 

 ern and southwestern pine bee- 

 tles, beneath the inner surface 

 of the bark. Very little appears 

 to be known of the seasonal his- 

 tory and habits of this species, 



Fig. 35.— The smaller Mexican pine beetle (Den- 

 droctonus mexicanus): Adult, greatly enlarged, 

 and section of egg gallery, slightly enlarged. 

 (Author's illustrations.) 



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Fig. 36. — The smaller Mexican pine beetle: Distribution map. (Author's illustration.) 



but evidently they will be quite similar to those of the southwestern, 

 southern, and Arizona pine beetles. It will therefore be subject to 

 the same general treatment for its control, namely, the removal and 



