58 INSECT ENEMIES OF THE BOLL WEEVIL. 



Type in. — This is the egg of Eurytoma tylodermatis, found by the 

 isolation of a larva seen in the act of hatching, collected at Dallas, 

 Tex., August 22. The egg is dark-gray and thickly covered with 

 spines. It measures 0.68 mm. in length and 0.21 mm. in breadth. 

 The process at one end is frequently twisted. (Plate II, fig. 4.) 



Type IV. — This egg was practically identified as that of a Cato- 

 laccus by isolation of specimens collected August 22 at Dallas, Tex. 

 The color is white and the egg is covered with very small tubercles or 

 papillae. It is 0.62 mm. long and 0.22 mm. broad. (Plate II, fig. 5.) 



Type V. — Tliis egg was taken only at Glenmora, La., August 23, 

 on two weevil stages, and has not been identified. It is dark-gray 

 and very spiny, but the spines are larger, longer, and sparser than in 

 Type III. The length is 0.44 mm. and the breadth 0.19 mm. (Plate 

 II, fig. 6.) 



Type VI. — This new type was discovered November 14 at Dallas, 

 Tex., and has not yet been identified. There is no sculpturing what- 

 ever. It is pure white. The length is 0.85 mm, and the breadth 

 0.19 mm. (Plate II, fig. 2.) 



THE LARV^. 



The larvse of the boll-weevil parasites live as readily on dead food 

 as on fresh food. The hosts generally die witliin a very short time 

 after the larvse begin attack. The larvse have been found pretty 

 well grown with dry weevil larvse as food. They have been found 

 on weevil larvse and pupse indiscriminately and several times under 

 the elytra of teneral or unemerged adults. Just before transforming 

 from the larva to pupa there is considerable meconial discharge. 

 The majority of the boll- weevil parasites are external feeders, but 

 the larvse of IlyiopTiasia senea, Ennyomma glohosa, and Tetrastichus 

 Jiunteri are internal feeders. These larvse kill the host in a short 

 time, its skin becoming shriveled and forming a perfect puparium 

 for the parasite. Pupation takes place within this skin. (PI. Ill, 

 figs. 5, 7.) 



Pupation. — All the chalcidoid parasites have naked pupse. The 

 braconids usually form silken cocoons of characteristic size, shape, 

 mesh, or color. The cocoons of Microhracon mellitor are very vari- 

 able in size, color, and consistency, so that they appear almost to 

 belong to different insects. The cocoons of SigalpJius curculionis are 

 generally of a rather bright yellow and with very fine silk. The 

 pupal exuvium of the various species of chalcids and braconids is 

 sufficiently characteristic to enable a skilled observer to determine 

 the species after the parasite has left. (PL III, figs. 1-4, 6.) 



Rapidity of development. — It is rather difficult to make an accurate 

 study of the developmental period of parasites, especially when every 

 adult parasite that matures under observation must be saved, if 



