ITiNTH Report of the State Entomologist 309 



has been directed by some Avriters, for the heavy vapor (about two and 

 one-half times heavier than common air) will descend and permeate the 

 mass and destroy the insect life — the beetle, the larvfc, or the eggs 

 deposited on the grain. After a day or two the bin may be opened for 

 the offensive odor to escape, and no injury will have been done to the 

 grain, either for flouring, for feeding, or for seed. 



It would be well in all cases where badly infested grain has been 

 treated in the above manner, especially when it is to be converted into 

 flour, to remove the dead insects by sifting or otherwise, as it is believed 

 that bad results have followed the use of flour into which the elytra 

 and dead bodies of the infesting insects had been ground up. 



In consideration of tlie explosive nature of bisulphide of carbon, it is 

 proper always to accompany the recommendation of its use with the 

 caution that a light or fire should never be brought near it. 



Pollenia rudis (Fabr.). 

 2 he Cluster Fly. 

 (Ord. Diptera: Fam. Muscid.e.) 

 Fabricius: Ent. Syst., iv, 1794, p. 314. 9 (as Musca rudis). 

 Macquart: Hist. Nat. Ins. — Dipteres, ii, 1835, p. 269 (as Pollenia). 

 Rob. Desvoidy: Hist. Dipt. Env. Paris, ii, 1863, p. 600. 

 LOEW: in Amer. Journ. Sci.-Arts, 2d ser., 1864, xxxvii, pp. 318, 321 (introduced 



from Europe). 

 Harris; Entomolog. Corr., 1869, p. 336 (as Mu sea familiar is). 

 Osten-Sacken: Cat. Dipt. N. Amer., 1878, p. 160. 

 Mann: in Psyche, iii, 1882, p. 378 (habits). 

 Ball: in Proc. U. S. Nat. Mus.. v, 1884, p. 635 (habits). 

 Riley: in Amer. Naturalist, xvii, 1883, pp. 82, 83; in Proc. U. S. Nat. Mus., v, 



1884, pp. 637, 638 (habits, synonymy, etc.). 

 Marlatt: in Insect Life, iv, 1891, p. 153 (killed by fungus). 

 LiNTNER: in Count. Gent., Ivii, 1892, p. 358 (general notice). 

 Riley-Howard: in Insect Life, v, 1893, p. 263 (in Illinois, habits, remedy, etc.). 



Pollenia rudis (the Musca rudis of Fabricius) was known and name 

 given to it in Europe a century ago. When it was introduced into this 

 country is not known, but commercial intercourse maj'- liave brought it 

 at any time either in its larval or perfect 

 stages. Dr. Loew, in an article iu Silliman's 

 Journal of Science, in 1864, mentions it in a 

 list of species of flies known to be common to 

 Europe and America. Of these, a number are 

 believed to have first made their appearance 



, , T^ . ,. , 1 -\ ^\ J. ^ Fig. 6.— The cluster fly, Polle- 



on the Facinc coast and gradually to have niaeudis. (After Macquart.) 

 worked their way to the Atlantic States. Presuming the P. rudis to 



