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139 



weevil population in the diflubenzuron treated area was no higher than the 

 initial overwintered population, but the population increa. ed 12X where con- 

 ventional chemicals were used. 



261. , and Brazzel, J. R. 1967. Phosphate insecticides and defoliants 

 applied singly and in combination for control of boll weevils. J. 

 Econ. Entoool. 60: 1027-1029. 



An experiment was conducted on a laboratory-reared, nondiapausing, susceptible 

 strain of boll weevils, Anthonomus grandls Boheman, to determine if certain 

 phosphate insecticides and defoliants were compatible when combined and 

 applied simultaneously. It was found that neither Def® (S,S,S-tributyl phos- 

 phorotrithioate) nor Folex® (tributyl phosphorotrithioate) inhibited the 

 lethal potential of methyl parathion, malathion, or azinphsomethyl. In fact, 

 the presence of a defoliant in mixture with an insecticide actually produced 

 a slight additive effect on the lethal potential. 



262. Gassner, G., Ill; Childress, D., and Klemetson, D. J. 1975. Spermiogenesis 

 in boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae) . 

 Int. J. Insect Morphol. Embryol. 4: 115-125. 



Spermiogenesis of Anthonomus grandis Bo^.eman, the cotton boll weevil, was 

 studied by transmission electron microscopy. The basic morphologic features 

 investigated and illustrated were: acrosome, nucleus, fibrous masses, micro- 

 tubules, and mitochondrial derivatives. A centriole adjunct was observed to 

 surround the basal body (centriole derivative) early in spermiogenesis, but 

 it subsequently disappeared. In the sperm tail, one mitochondrial derivative 

 developed into a rod-like structure that inserted into a concavity at the base 

 of the nucleus and terminated near the end of the tail. This mitochondrial 

 derivative may provide a rigid base for the undulating membrane. In addition, 

 the attachment of the rod to the nucleus may serve in a manner analogous to 



