8 BULLETIN 416, U. S. DEPARTMENT OF AGRICULTURE. 
the leaf surface or among the fibrils of the webbing and rarely in- 
volve an area greater in size than that of a dime. 
TaBLE II.—Duration of the egg stage of the red spider. 
Average Mean 
Brood. | date of aeoree | Average | tempera- 
: i 'duration.| ture for 
tion hatching. period. 
Days. | Ee 
1s ee Mar. 12 | Mar. 27 15.0 a4 
ise | Mar. 24| Apr. 4] . 115] 58 
BE en se | Apr. 4] Apr. 13 10.0 60 
cE Apr. 27 ay 3 6.0 67 
poets | May 19 | May 23 4.0 75.2 
Cees June 10} June 13 4.0 81 
(eee ae July 16 | July 19 3.5 80.7 
eee Aug. 20 | Aug. 23 4.0 79.8 
ee Sept. 2| Sept. 5 40| 78.9 | 
1G Sept. 11 | Sept. 18 8.0 69 
i eee Sept. 14 | Sept. 19 6.0 | 70.5 
122 3c Sept. 30 | Oct. 7 | 8.0} 68.3 
1225s: Octawst Nov. 16 | 17.0 | 58.9 
THE LARVA. 
Description.—The newly hatched larva (Pl. II, fig. 2) is round, 
colorless, and 6-legged, and its body does not exceed that of the egg 
MAP. APR. MAY SNE SULLY ALG. SLP7~ OC” WOK 
TE/YFLERMATUKE DEGRLES FF 
Ars 
Fic. 2.—Simultaneous curves of temperature and incubation of the red spider, showing the intimate rela- 
tion between prevailing temperature and the time required for the development of theegg. (Original.) 
in size. The two portions of the body, cephalothorax and abdomen, 
are rather distinctly marked at this time by a transverse suture. 
The most conspicuous feature of the newly-hatched larva is its 
bright carmine eyes. It begins feeding at once, and as feeding pro- 
gresses the larval color deepens to a green or ferruginous green. A 
characteristic feature of the larva is the shortness of the legs due to 
inflation of the shghtly hardened leg segments. Although the tarsus 
and the femur are the longest joints of the larval legs, there is no 
