12 



BULLETIN 833, U. S. DEPARTMENT OF AGRICULTURE. 



pads, and legs are dark brown, and the abdomen orange. The 

 cephalic horns are distinct in the nearly mature form of the pupa. 



When mature the pupa works its way out of the gall. On emer- 

 gence a split is made upon the dorsal line of the head and thorax of 

 the pupal case through which the adult issues. (PI. I, A, D.) During 

 emergence the adult is very active and issues very rapidly. 



From the time that the larva enters the tissue to the first sign of a 

 swelling, or gall, observations on 18 life-history cages show that a 

 period ranging from 4 to 14 days elapsed with an average of 7 days 

 (see fourth column of Table III). The young gall may now be 

 readily recognized by the characteristic white spots, or slight swell- 

 ings. 



It takes from 21 to 46 days, with an average of 28 days, from the 

 time at which the larva first enters the tissue until the emergence 

 of the adult. These observations were taken from the results obtained 

 from 18 cages during the spring of 1917 and the spring and fall of 

 1918, as is shown in the following table. Britton (32) found it to 

 require from 20 to 50 days to transform within the gall. 



Table III. — Time required from: (a) larva entering tissue until first sign of gall; (b) larva 

 entering tissue until emergence of adult. 



Cage. 



Larva entering tissue. 



Apr. 7-11. 



do. 



do. 



....do. 



1917. 



1918. 



Feb. 7 



do 



Mar. 6-12 



Mar. 6-10 



Mar. 12 



....do 



....do 



do 



Aug. 31 



Sept. 2 



Sept. 4-14 



Sept. 4-11 



Sept. 7-14 



Sept. 24-25.... 



First sign of gall. 



Feb. 13-16. 

 .do. 



Mar. 15 



do 



Mar. IS 



Mar. 10 



Mar. 18 



do 



Sept. 9-19.. 



Sept. 9 



Sept. 17.... 

 Sept. 11.... 

 Sept. 14-19. 

 Oct 2 



Time, 

 required 



(a). 



Days. 



Date of emergence. 



7 

 7 

 6 

 7 

 6 

 14 

 6 

 6 

 214 



7 

 8 

 7 

 6 



8 



Apr. 29 to May 2. 



Apr. 30 



Mav 1-2 



Apr. 30 to Mav 2. 



Mar. 4 



Mar. 4-7.. 

 Apr. 6-22. 

 Apr. 8-22. 

 Apr. 27... 



do.... 



Apr. 6.... 



Sept. 25 



Oct. 2 



Sept. 20 to Oct. 3. 

 Sept. 27 to Oct. 2. 

 Oct.4 



Oct. 24 to Nov. 2. 



Total 



length 



(b). 



Day*. 



"22 



121 



23 



22 



25 

 26 

 36 

 38 

 M6 

 2 4r, 



25 



25 

 30 

 121 

 22 

 23 

 34 



1 Minimum, time. 



2 Maximum time. 



From Table IV it is evident that the total life cycle requires from 

 27 to 52 days, with an average of 35 days. These data represent 

 the results obtained from 17 life-history cages under Washington 

 conditions. There is a constant overlapping of broods when the 

 greatest numbers are present, namely in the spring and fall of each 

 year. The aestivation period has been found to extend, in Maryland, 

 Virginia, and the District of Columbia, from the early part of June 

 to the latter part of August. 



