22 



MISC. PUBLICATION 273, U. S. DEPT. OF AGRICULTURE 



The different species of this genus and the hosts from the seed of 

 which they have been reared are as follows : 



Species Hosts 



Mcgasiigmus aWifrons Walk Ponderosa piue. 



Mcgastigmus Jasiocarpae Crosby Alpine fir. 



Megastigmiis picea Rohw Blue spruce, Engelmann spruce, and Sitka 



spruce. 

 Megastigmvs pinus Parfitt Silver fir, lowland white fir, white fir, 



Shasta fir, and bristlecone fir. 



Mcgastigmus tsugae Crosby Mountain hemlock. 



Megastigmus s p e r m o t r o ph u s 



Wachtl {60) _ Silver fir, bristlecone fir, grand fir, red fir. 



white fir. Douglas fir, and other conifers' 



FiGUKh '.) A Mwu Ij. Adults of the ponderosa pine seed chal- 

 cid (Me(ja-,tiyiini^ albifrons) laying eggs through small 

 green cones into seeds (drawings by Edmonston). En- 

 larged. C^ Larvae, pupae, and adults of same species of 

 Megastigmus, X 3. Female above, male below. 



NUT AND ACORN 

 WEEVILS 



Nuts and acorns of 

 various western hard- 

 woods are frequently' 

 infested by the 

 curled white grubs 

 of the nut and acorn 

 weevils, belonging to 

 the genus Balaninus. 

 The adults are me- 

 dium-sized, yellow, 

 brow n, or nearly 

 black weevils with 

 robust bodies, long- 

 legs, and prominent, 

 slender, curved or 

 nearly straight beaks. 

 The adults appear in 

 the summer. With 

 their beaks they 

 gnaw holes in the 

 shells of new acorns 

 or nuts and in these 

 they place their eggs. 

 The larvae feed on 

 the meat and destroy 

 the seed. The win- 

 ter is passed in the 

 larval stage, either 

 within the acorn or 

 in the ground. Pu- 

 pation occurs the 

 next spring, and the 

 adults emerge in the 

 summer. Several 



