﻿5"HE CATTLE GEUBS OS OX WARBLES 



9 



several larval stages of H. lineatuni from the Punjab. He also fur- 

 nished data showing an infestation of slightly over 35 per cent of 

 some 41,000 head of cattle which he examined in different parts of 

 the Punjab. C. W. Howard has written that he has never seen 

 H3q3oderma larvae in southern China, except in cattle that were be- 

 ing imported. C. P. Clausen made some inquiry regarding the oc- 

 currence of Hypoderma in JNIanchuria in 1923. He informed the 

 writers that although cattle in that Province were not infested, those 

 from Mongolia were heavily infested. Clausen's informant stated 

 that although many infested cattle were brought into Manchuria 

 from JNIongolia, they became free from grubs in one year. Clausen 

 also learned from Dr. PI. Okamoto that near Sapporo, Japan, there 

 is a small locality in which this pest has become established, prob- 

 ably through introductions of cattle from America. Doctor Mat- 



FiG. 1. — Distribution of Hypoderma liueatum in the United States. Bach dot repre- 

 sents a locality where this species has been collected during this investigation 



sumura also informed Clausen that H. bovis occurs on cattle in the 

 vicinity of Akita. 



Through correspondence and by personal examinations by agents 

 of the bureau, the distribution of the cattle grubs in the United 

 States and their relative abundance have been determined with fair 

 accuracy. A summary of the information on this subject was pub- 

 lished Ijy one of the writers in 1915 (4), and Mote (09) lias made a 

 valuable contribution regai'ding the distribution of Hypoderma in 

 Ohio. A study of the accomi)anying maps (figs. 1 and 2) will best 

 ilhistr-ate the distribution of the two species of Hy])oderma in the 

 United States. It is apparent that //. Uneatum is much more widely 

 and generally distributed in this country than is //. hoim: in fact, the 

 entire area whe.-e //. hovis occui'S is also infested with //. Irruuifmn. 

 The former species had never been recorded in the United States up 

 to 1910 {ijf)). Kil(!y (H'l), basing liis infoniiation on a number of 

 colhictions mainly from the Central and Sonthcin States, concluded 

 that probably //. IjooIh did not (K-cur in this country. Hadwen {'M) 



