12 



BULLETIN 901, U. S. DEPARTMENT OF AGRICULTURE. 



Table VIII. — Time and duration of period in ground of A. chalybea, North East, Pa., 



1917. 



Date of 

 entering 

 ground. 



Date of 

 emergence. 



Number 

 of indi- 

 viduals. 



Duration 

 of period. 



Date of 

 entering 

 groundj 



Date of 

 emergence. 



Number 

 of indi- 

 viduals. 



Duration 

 of period. 



June 28 

 July 2 

 4 

 .5 

 7 

 8 

 8 

 9 

 10 

 10 

 10 

 11 



July 23 1 

 27 3 

 26 2 



26 1 



27 1 



27 , 4 



28 3 

 30 I 1 



28 i 1 



29 1 



Days. 

 25 

 25 

 22 

 21 

 20 

 19 

 18 

 21 

 18 

 19 

 20 

 17 



July 11 

 11 

 13 

 13 



■ \i 



15 

 15 



15 

 17 



17 



July 30 



Aug. 1 



July 31 



Aug. 2 



2 



July 31 



Aug. 1 



3 



1 



4 



2 

 1 

 2 

 2 

 3 

 1 

 1 

 1 

 3 

 1 



Days. 

 19 

 21 

 18 

 20 

 19 

 16 

 17 

 19 

 15 

 18 



28 



4 



i 42 



2 19. 24 



1 Total. - Weighted average. 



Described from a large series of beetles reared at North East, Pa., under Quaintance 

 No. 16427. 



Type.— Oat. No. 22290, U. S. National Museum. 



PI. I, C. 

 Similar to that of Altica chalybea. Length 0.75 mm., width 0.35 mm. 

 Color straw yellow. Brownish strand much larger proportionately than that of the 



"large form," about one-half the length of the egg. 



The size and color are as described by Comstock (12). 



Table IX. — Prepupal period of 

 A. chalybea, North East, Pa., 

 1917. 



Number of 

 prepupae. 



Duration 

 of period. 



2 

 2 

 11 



4 

 4 



Days. 



7 



8 



9 

 10 

 13 



i 23 



2 9.17 



i Total. 

 2 Weighted average. 



THE LARVA. 

 PI. II, A. 



Similar to the larva of the ' ' large form " (A . chaly- 

 bea) but much smaller. The chitinized areas are 

 smaller proportionately and the fully fed larva is 

 distinctly yellow without the brownish color ele- 

 ment. The setae on the ventral prothoracic seg- 

 ment are wanting. Width of head: First instar from 

 0.292 to 0.312 mm. , average 0.306 mm. ; second instar 

 from 0.435 to 0.458 mm., average 0.453 mm.; third 

 instar 0.577 to 0.624 mm., average 0.612 mm. 

 Average length of full grown larva 5 mm. 



THE PUPA. 



PI. II, B. 

 The writer knows of no characteristic by which this pupa may be distinguished 

 from that of its larger relative except that of size. The average length is 3.5 mm. 



Table X. — Pupal stage of A. chaly- 

 bea, North East, Pa., 1917. 



Table XI. — Callow period of adult 

 stage of A. chalybea, North East, 

 Pa., 1917. 



Number of 

 pupse. 



Duration 

 of period. 



4 

 4 

 6 

 3 



Days. 

 7 

 8 

 9 

 10 



117 



= 8.47 



Number of 

 individuals. 



Duration 

 of period. 



4 

 13 

 2 

 1 



Days. 

 1 

 2 

 3 

 4 



120 



2 2 



i Total. 



2 Weighted average. 



1 Total. J Weighted average. 



