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BULLETIN 1369, U. S. DEPARTMENT OF AGEICULTUEE 



Only four adults oi H. Uneatum were bred out in Middletown, 

 N. Y. Among these the pupal period ranged from 26 to 41 days, and 

 the period from date of leaving the host to emergence of the adult 

 ranged from 27 to 42 days. At Dallas, Tex., this period of trans- 

 formation ranged between 18 and 77 days, with an average of 41.7 

 days in the case of 221 specimens kept out of doors. 



The average period of transformation was slightly shorter in males 

 than in females, being 42 days in the former and 44.4 in the latter, as 

 computed on 92 males and 80 females. ' 



Hadwen {33) has presented records of the duration of the pupal 

 stage of H. Uneatum of from 13 to 19 days when the specimens 

 were kept in an incubator at 32° C, and Glaser {30) records a pupal 

 period in Germany for this species of 23 to 38 days. Carpenter 



{12^ 17) states that 

 he has observed the 

 pupal period to be 

 about 7 to 8 weeks in 

 Ireland. 



PREPUPAL AND PUPAL 

 STAGES OF HYPO- 

 DERMA BOVIS 



Mature larvse of 

 H. hovis show about 

 the same degree of 

 activity after emer- 

 gence from the host 

 as those of H. Une- 

 atuTn, but they seem 

 to have a stronger 

 tendency to burrow 

 into the soil. The 

 larvse of this species 

 also show a great de- 

 sire to escape from direct sunlight, and one was observed to crawl 

 12 feet to a deep shadow, where it pupated. If placed on loose soil, 

 most of them will bury themselves in a short time. Some burrow 

 down about an inch, but most of them go just below the surface. 



When the weather is warm the prepupal period is very short. At 

 Dallas records were kept on several larvse which emerged normally 

 from cattle. All of these pupated, and 4 produced adults. The 

 prepupal period of these larvse was in every case somewhat less than 

 a day, and the pupal period of the 4 Avhich emerged was from 14 

 to 15 days, making a total period from emergence from the host to 

 the appearance of the adult insects of from 15 to 16 days. Among 

 24 larvse extracted from cattle at Dallas, Tex., and kept for rearing, 

 14, or 58.3 per cent, pupated and only 1 (4.2 per cent) produced 

 an adult. In the case of this specimen the prepupal period was 

 slightly more than a day, and the pupal period 14 days, a total 

 transformation period of 15 days. The writers succeeded in breed- 

 ing out 4 adults from 8 mature larvse extracted from cattle at 

 Herkimer, N. Y. (Table 9). The prepupal period among these was 

 10 hours to 1 day, and the pupal period from 15 to 24 days. The 

 total developmental period from extraction of the larvse to the 



Fig. ol. — Heifer with bagging arouud body, for purpose of 

 collecting cattle grubs as they emerge from host 



