On Certain Seed-Ixfesting Chalcis-Flies. 383 



U. S. National Museum there are a series of specimens reared from 

 rose seeds imported from Peking, China, 



THE DOUGLAS FIR-SEED CHALCIS 



{Megastigrnus spermotropJms Wachtl) 



While a native of the western United States this insect has been 

 reported only from Europe where it has become a serious pest. It was 

 first described in 1893 by Wachtl, i' from specimens reared from seeds 

 of the Douglas Fir imported into Europe from the western United States. 



In 1906, Dr. R. S. MacDougall published an account of a serious out- 

 break in Aberdeenshire, Scotland. He quotes a letter from Mr. John 

 Crozier of that place in which he says, ' ' Now, however, it has assumed 

 a more serious aspect, as the seed on many of the older trees from which 

 I formerly collected my supply, in good years amounting to over 300 

 bushels, is now not worth the trouble of gathering. I have raised 

 some millions of plants on thin estate, but unless the pest can be kept 

 in check, it will be impossible to keep up the stock from home grown 

 supplies. ' ' 



An American insect which has proved itself so injurious abroad should 

 not be neglected at home, particularly in view of the increasing interest 

 in forestry and the consequently greater demand for the seeds and 

 seedlings of forest trees. In a packet of Douglas Fir seeds received 

 from a nursery firm and supposed to have been collected in Colorado, 

 we found a number of seeds containing larvce probably belonging to 

 this species. 



In November 1908, we received from Mr. John Crozier of Scotland a 

 package of very badly infested seeds of the crop of 1907. While the 

 exit holes in many of the seeds were evidence that a large number of 

 adults had emerged, full-grown larvse were found in the remainder. 

 MacDougall also mentions rearing the adults from two-year-old seed. 

 These seeds were placed in a cage in a warm greenhouse and on Decem- 

 ber 7 th the males began to appear, followed on the 24th by the first of 

 the females. 



We have been unable to find any description of the manner of ovi- 

 position. The egg as obtained by dissection of the female is white, 

 smooth and spindleshaped with a very long pedicel at the anterior 

 end and the vestige of one at the opposite end. Length of body of 

 egg, .36 mm.; tail-like process, .9 to 1.2 mm. (Fig. 87). 



The full-grown larva is yellowish white with brownish mouth parts; 

 its length varies from 2.5 to 3.5 millimeters. The surface is smooth 



•' Wien. Ent. Zeit., XII., p. 24. 



