32 



gooseberry, third on poplar, fourth on elm and blackberry, fifth on 

 apple, sixth on hickory and willow, and eighth on oak. It is appar- 

 ently the species whose larvae were mainly responsible for the heavy 

 injury to crops in northern Illinois in 1912, as shown by its numbers 

 in -Davis's collections there in 1914. It was then the leading species 

 in that part of the state, comprising more than 60 percent of the 

 13,521 May-beetles obtained by him there that year. 



PJiyllopJiaga inversa Horn 



Inversa is limited to northern and central Illinois, and is espe- 

 cially abundant, apparently, in the central part of the state, where it 

 made 12.4 percent of all the May-beetles of our collections, as com- 

 pared with 8.8 percent in northern Illinois. Curiously, not a speci- 

 men of this species was found among the more than 20,000 obtained 

 by us in the southern part of the state. In northern Illinois it was 

 fifth in point of numbers, being surpassed there by fusca, futilis, 

 rugosa, and anxia, while in central Illinois it was the third species, 

 only Jiirticula and implicita being more numerous. 



In 1907 inversa was a dominant May-beetle in Champaign county, 

 where it made 27 percent of our collections and was second only to 

 implicita {implicita, 6964; inversa, 5157). In 1908 and 1909 we 

 found no evidence of its dominance anywhere, our northern Illinois 

 material containing only 4 percent of inversa in 1908 and 7 percent 

 in 1909 ; and our central Illinois collections, 2.4 percent and 4 per- 

 cent in those years, respectively. In 1910 it was again dominant, with 

 liirticula, in Champaign county, 39.7 percent of our collections there 

 belonging to liirticula and 32.6 percent to inversa. The same was 

 true, however, in 1911, when liirticula contributed 63 percent to our 

 Urbana collections (6501 out of 10,203 specimens) and inversa 21 

 percent. In 1913 it was apparently a dominant species at Aurora, in 

 northern Illinois, second there only to fusca {fusca, 47 percent; in- 

 versa, 36.6 percent of our 1940 specimens). 



Our earliest captures of inversa in northern Illinois varied in 

 different years from April 15 to May 22 and in central Illinois from 

 April 20 to May 9. Its latest occurrences fell between June 21 and 

 July 9 in the northern part of the state and between June 13 and 

 July 5 in central Illinois. Its periods of greatest abundance ranged 

 from the middle of May to the middle of June at the north and from 

 about the middle of April to the last of May in central Illinois. 



In respect to its favorite food-plants, inversa differs radically 

 from most of our species. It belongs neither in the oak-hickory nor 

 in the poplar- willow groups; on the other hand, it is third on our 

 list of elm species {anxia, 33 percent from that tree; ilicis, 17.2 per- 

 cent; and inversa, 14 percent) : second of our apple species {implicita, 

 32.6, and inversa, 19.6 percent) ; and second also on the blackberry 



