. Bulletin of the Department of Agriculture. Agriculture. 84 J!L LLKTKN 427, V. is. DEPARTMENT OF AGRICULTURE, DIHRACHYS BOUCHEANUS RATZ.' This well-kiiowii and cosmopolitan secondary parasite (lig. 17) oniorp'd from the tubor-moth material collootod during 1912, 1913,. and 191 I, and, as slunvn by dissection, from both Hahrohracon,. a * c * ^b Fig. 17.—Dibrachys houcheanus: a, Larva; 6, pupa; c, adult female; d, heul of larva; e, antenna of ' male, highly magnified. Greatly enlarged. (After Howard.) johannseni and Chelonus slioshoneanorum, the former seeming to be its favorite host. Tlii
. Bulletin of the Department of Agriculture. Agriculture. 84 J!L LLKTKN 427, V. is. DEPARTMENT OF AGRICULTURE, DIHRACHYS BOUCHEANUS RATZ.' This well-kiiowii and cosmopolitan secondary parasite (lig. 17) oniorp'd from the tubor-moth material collootod during 1912, 1913,. and 191 I, and, as slunvn by dissection, from both Hahrohracon,. a * c * ^b Fig. 17.—Dibrachys houcheanus: a, Larva; 6, pupa; c, adult female; d, heul of larva; e, antenna of ' male, highly magnified. Greatly enlarged. (After Howard.) johannseni and Chelonus slioshoneanorum, the former seeming to be its favorite host. Tliis species was reared from the egg in the laboratory, where it attacked the mature larvae of its hosts after they had spun their cocoons. Wliere the cocoons were not too thick to prevent it from reaching its host tiie parasite would often feed at the wounds caused by its ovipositor. "\Ylien roared under laboratory conditions thohvperparasites in- crease rapidh", but under field conditions their numbers are not as large in proportion to the host as might be expected. During 1912 and 1913 the percentage of para- sitism ran as high as 50 per cent in the case of llahrohracon jolmnnseni. With Chelonus shoshoneanorum the average was much lower, the highest running 29p(^r cent. During 1914 the percentages in >)oth cases were much reduced, and wliile greater numbers ol its two hosts were reared than in the previous year, Dibrachys houcheanus was noted on only a few Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Dept. of Agriculture. [Washington, D. C. ?] : The Department : Supt. of Docs. , Govt. Print. Off.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
