FAMILY SCOLYTIDAE 



519 



XiZ 



their hosts until they have become full-fed and eaten out the pupal 

 chamber, since the pupae of the flies were often found in the latter. 

 They are deep metallic blue in 



colour, with green reflexions, the head /-~;,v- 



and the thorax being dull coppery. The •. / 



eyes are brilliant crimson. In the 



larger of the flies the wings have a 



transverse brown band across them 



about half-way up. The figures show 



these two flies. 



Niponius canalicollis, Lewis. — The 

 grub of this beetle is predaceous upon 

 the grubs of the Polygraphm and the 

 Phloeosinns beetles. The insect has been 

 already described on p. 507. 



The Colydiid Beetles.— The larger 

 of these is predaceous upon the Poly- 

 <^raphm beetle. In the galleries of 

 the Polygraphus I discovered numerous 

 smallish white eggs laid several to- 

 gether, and simply deposited on the 

 floor of the gallery. From their posi- 

 tion, and the fact that male and female 

 colydiid beetles were taken together in 

 the Polygraphus galleries, I consider 

 that these eggs are those of the larger 

 of the colydiid beetles, and are laid 

 in this position to 



334- 



Flies parasitic on P. treiuhi. 

 North Zhob. 



enable the larvae 



on hatching out 



to feed upon the 



eggs or larvae of the Polygvaphm beetles. I took a 



male and female of this insect together in one of the 



egg-tunnels of the Polygraphus beetle. 



The smaller of the colydiid beetles may con- 

 fine itself to the Phloeosinus bark-borer, or ma\- be 

 predaceous upon one of the enemies of the bark- 

 borers. 



Beetle. — Lis:(ht l^rown in colour, with a prominent head 



X/?. furnished with large black eyes and short antennae; the thorax 



Fu;. ^35. is square and pitted, as also are the elytra, which leave the 



Beetle predaceous upon tip of the body exposed. Fig. 335 shows the larger of the 



/'. ireiicJii. North Zhob. two colvdiid beetles. 



