178 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



plants, as enumerated above, seem to be much more preferred for pur- 

 poses of oviposition. With this fruit the eggs are inserted singly at 

 the sides of the dormant buds in the fleshy region at the axils of the 

 leaves. 



This species derives its economic importance largely from its injurious 

 work on apple trees, especially in neglected plantings, which sometimes 

 are quite badly scarred as a result of the wounds caused by the ovi- 

 position punctures. The penetration of the tissues by the ovipositor 

 may apparently be also attended by infection with some unknown 

 fungus or bacterial organism, which not infrequently forms a canker, 

 indistinguishable in its external appearance and effects from the New 

 York apple-tree canker (Sphaeropsis malorum Pk.) or the blight canker 

 of apple trees {Bacillus amylovorus [Burr] de Toni). The woolly aphis 

 may also establish itself in wounds made by this cricket and thus 

 aggravate the primary injuries. 



The species nigricornis differs in its oviposition habits from niveus 

 by depositing its eggs in long rows. It prefers for the reception of its 

 eggs raspberry, blackberry, horseweed {Erigeron canadensis L.) and 

 goldenrod, Solidago spp. Oviposition occurs to a less extent in twigs 

 of willow, elder, maple, elm, sumac, grape and peach. This species 

 has been discussed by many writers under the name of niveus, and 

 judging from the accompanying illustration in their accounts it would 

 appear that nigricornis deposits its eggs in a great many plants in 

 addition to the foregoing, as currant, artichoke (Helianthus spp.), 

 Ambrosia spp., cottonwood, box elder, cherry, dogwood, black lo- 

 cust, sycamore, ash, honey locust, and catalpa. This cricket is some- 

 times quite destructive in raspberry plantings as the wound made by 

 the deposition of so many eggs may cause the death of the terminal 

 growth of the shoot or loss of fruit from the breaking off of the cane 

 at the point of injury. 



The species quadripunctatus may be observed occasionally in rasp'*^ 

 berry plantings in company with niveus and nigricornis. It is, how- 

 ever, of no economic importance. It oviposits in weeds, principally 



Oecanthus niveus, a. — 1, Apple wood showing egg punctures and diseased 

 areas, xl|; 2, Egg at base of petiole in raspberry, showing normal oviposition in 

 this plant, x2§; 3, Egg, showing its position in apple bark, xl5; 4, Egg cap show- 

 ing spicules, x50; 5, Spicule showing characteristic outline, x500. 



Oecanthus nigricornis, B. — 1, Row of egg punctures in raspberry, xl|; 2, 

 Longitudinal section of the same, x3; 3, Egg, xl5; 4, The egg cap, x50; 5, A 

 single spicule of the cap, showing characteristic outline, x500. 



Oecanthus quadripunctatus, C. — -1, Egg punctures in wild carrot {Daucus 

 carota), xl|; 2, Longitudinal section of the same, x3; 3, Egg, xl5; 4, Cap of egg, 

 x50; 5, A spicule of egg cap, showing characteristic outline, x500. 



