THE EXPERIMENT STATION. 151 



The grub or larva is cream colored. The head is prominent, the jaws 

 large, and three jointed thoracic feet are plainly visible. It is a little longer 

 than the beetle, or about 4 mm. long. 



The pupa is a little shorter than the beetle. It is the same color as the 

 larva, and has spinous projections on the sides of both the thorax and 

 abdomen. 



REMEDIES. 



When these beetles are in a close box or bin, nothing is more effective to 

 destroy them than is bisulphide of carbon. This very volatile liquid soon 

 evaporates, and the deadly fumes are so penetrating that few beetles, even 

 in a bin of grain, escape alive. In a bin or barrel the liquid can be applied 

 at the bottom as follows: A piece of gas pipe, with a close fitting rod in it r 

 is pushed into the grain. The rod is then withdrawn and the liquid poured 

 into the pipe ; after which the latter is quickly drawn out. A piece of oil 

 cloth or a carriage robe spread over the bin or barrel to confine the vapors, 

 aids the work. This remedy is excellent in all cases of insects that infest 

 stored grain. There is only one objection — the danger of fire. This vapor 

 is highly inflammable and explosive. A burning match or a lighted cigar 

 might cause a disastrous explosion. It is to be said, however, that the 

 vapors are soon dispersed, so that open doors and windows soon remove all 

 danger. We see, then, that caution and a brief guarding of the premises are 

 all that is required to remove all danger. At my suggestion one of the 

 largest flour manufacturers of Michigan has entirely cleared one of his mills 

 of insects, though the mill was terribly infested, by this remedy. His mill 

 is in the very center of one of our largest cities; yet he was cautious and no 

 danger was incurred. He buys his bisulphide of carbon by the barrel of the 

 manufacturer at Cleveland, Ohio. Of course no one should breathe the 

 poisonous vapors. In the case at Detroit we found that paper spread with 

 lard or other grease would attract the beetles in prodigious numbers, when 

 they could be easily and quickly destroyed. In this case they were so widely 

 distributed that the bisulphide of carbon was not a practical remedy. 



SQUASH BUG PARASITE. 



Few of our noxious insects are more destructive or harder to combat than 

 is the large dark colored squash bug, Anasa (Coreus) tristis De Geer. The 

 method of trapping under chips, and of shaking into shallow vessels con- 

 taining kerosene, though the best known remedies, are not very satisfactory. 

 Thus I am happy to report that I have raised a dipterous parasite from this 

 insect. This fact is doubly interesting, not only from the destructiveness 

 of the bug, and the difficulty in combating it, but it gives a page in the life 

 history of the fly which was before unknown. 



TRICHOPODA PENNIPES FABR. 



This fly has long been known as a common insect about gardens, but its 

 habits or life history have not been previously known so far as I can learn. 

 Dr. S. W. Williston writes me that he has this insect from all over the 

 United States, from South America and St. Domingo. He further adds 



