206 



50,000 in number, set late in June. These have been attacked and many 

 of them destroyed by the adults of two species of llhynchophora (/>/.s- 

 tronotus appendicnlatus Boh. and Erycvs puncticoUi.s Ticc.). Tlie former 

 is supposed to be the chief depredator, though I myself : aw the latter 

 attacking the plants. First, great cavities are gouged out of the stems 

 of the young' plants, and later the bases of the larger leaves are attacked 

 from beneath. Both secrete themselves in the ground about the plants, 

 and I took ten individuals of the Listronotus from about a single plant. 

 It is not unlikely that one and perhaps both of these species breed in 

 Sagittaria, though I have some reasons for suspecting that the Erycus 

 may breed in the common Typha latlfoUa or cat-tail. 



A minute Thrips, in all probability Limothrip.s iritici Pack., as 

 determined by Mr. Th. Pergande, through the courtesy of Mr. How- 

 ard, IT. S. Entomologist, has caused serious injury to the onion crop, 

 seeming to be very generally distributed over the State, This little 

 pest appears to breed in enormous numbers among the tops of the 

 onions, well down toward the crown of the plant, where the close prox- 

 imity of the young, tender growth renders destructive measures well 

 nigh imi^ractical, and, besides, places the young Thrips beyond the 

 reach of the majority of its natural enemies. Still, continual repro- 

 duction compels the little pests to sooner or later leave their coverts, 

 especially after reaching maturity, and they are then devoured by the 

 swarms of little red and black ladybirds {Megilht maculata De G.), 

 which, judging from the number of them present in the onion fields, 

 must exert a powerful influence in holding the pest in check during 

 (trdinary years. The most useful parasite, however, is the larva of a 

 small Syrphus fly belonging to a species not yet determined. These 

 maggots are to be found down among the younger portions of the 

 tops, near the crown, and right in the midst of the young Thrijis, which 

 they devour precisely as aphides. We have found that apjdica- 

 tions of a strong decoction of tobacco water, or a mixture of 1 part 

 crude carbolic aci<l to 100 parts water killed all that were in reach, 

 but so many are so entirely protected in their secluded nooks in the 

 crown of the plant that repeated applications are necessary. For 

 some reason the injury has been more emphatic on the higher lands. 

 In the vicinity of Lodi, Ohio, there are several hundreds of acres of 

 onions, cultivated for the most part on redeemed swamp lands where 

 the soil is of a peaty nature, but with an occasional knoll of clay. 

 Comparatively little injury has been done on the low, wet, peaty 

 soil, while on the clay the destruction is almost total. 



A number of years ago, while living in Indiana, I observed adults of 

 Ligyrus gihhosiis De G. depredating on carrots in the fields. This 

 year the same insect came to me likewise from Indiana, accused of 

 destroying sunflowers by eating the roots, going from hill to hill to 

 continue their depredations. This character has been recorded of the 

 species west of the Mississippi River, but not, I believe, farther east. 



