CACTUS-FEEDING INSECTS AND MITES 95 



At Uvalde in September the minimum and maximum periods were 

 5 and 20 days respectively; the variation in development was as great 

 as 12 days among eggs laid on the same day and kept at the same 

 storage temperature. Eggs subjected to a chill room temperature of 

 45° F. for 50 days have hatched successfully, but the mortality in- 

 creased rapidly after 35 days at this temperature. In these experiments 

 some eggs hatched in December after an incubation period of 79 days, 

 34 days after removal from the chill room. Desiccation of the eggs 

 causes serious mortality, and it is probably one of the main factors 

 affecting the prevalence of all species of Moneilema. In rearing these 

 insects in cages exposed to the sun and wind, better results have been 

 obtained when periodical watering during dry weather was practised 

 in order to prevent drying out of the eggs. 



The duration of the pupal stage has not been ascertained. However 

 the time spent in the cocoon, i.e., the prepupal and pupal stages, 

 varies very greatly, from 3 to 4 weeks in summer to 6 to 7 months in 

 October to April. 



Of the two chalcid parasites known, the encyrtid Ooencyrtus ovidivorus 

 (Girault ^) has on various occasions been active in destroying eggs 

 in the Uvalde cages in March to May and in July to October. The 

 pteromalid Neocatolaccus moneilemae (Gahan ^) is a pupal parasite, or 

 rather, emerges from the cocoons. As many as 35 individuals have 

 been reared from one cocoon. Adults have been bred in June, August, 

 and September. This insect severely attacked cocoons in cages at 

 Uvalde in September 1929. 



Moneilema variolate Thomson 



This insect is closely related to M. ulkei; some forms of M. variolare 

 are scarcely distinguishable from its ally. The adults are quite variable. 

 Both sexes may be wholly dull black, or the elytra and sometimes 

 the prothorax may be irregularly marked with white. In one extreme 

 form, the elytra and prothorax of the female are patterned with 

 a network of wavy white lines. The density of the punctures on the 

 prothorax and elytra shows marked variation. 



This dominant member of the genus occurs on the Central Plateau 

 of Mexico, where it is more abundant than any other Moneilema 



1 Girault, A. A., "An essay on when a fly is lovable, the ceremony of baptizing 

 some and unlovely hate." Brisbane, privately printed, Jtme 30, 1925, 4 pp. De- 

 scription of Echthrodryinus ovidivorus, new species, appears on page 3. 



2 Gahan, A. B. "A new encyrtid parasitic in the eggs of Moneilema (Hymenop- 

 tera:Chalcidoidea." Proc. Ent. Soc. Washington, vol 27, no. 8, p. 167, November 

 1925. Description of Neocatolaccus moneilemae, new species, appears on page 167. 



