480 Phylum Arthropoda 



Mealworms were reared under environmental conditions similar to 

 those of the bean weevil. The optimum food for this species is not 

 definitely known. Excellent results have been obtained by rearing them 

 on a prepared dog meal containing dried vegetables, cereals, and meat, 

 or in dog biscuits containing the same general ingredients. 



Cultures were started in pint jars with about 100 eggs per culture. 

 When the larvae reached a moderate size the culture was divided so that 

 only 40-50 larvae were reared in one culture. When the larvae are 

 small they require little attention but in late larval instars the food 

 should be changed at least twice a month. 



When ready to pupate the larvae come to the top of the meal and pass 

 into a quiescent state. This prepupal state may be readily recognized 

 and such individuals may be removed from the culture if desired or the 

 pupae may be removed at definite intervals. 



After emergence the adults were placed in ovipositing cages similar 

 to those of the bean weevil. The false bottom in the case of the meal 

 worm adults contained whole wheat flour sifted through a 7 2 -mesh silk 

 screen. The adults oviposited in the flour through the wire screen and 

 the eggs were readily separated from it by sifting through a 30-mesh silk 

 screen. The mealworm adults feed, and the rate and amount of ovi- 

 position depends to a great extent on the food that the adults receive. 



Dog biscuits and canned dog meat were used as food for the oviposit- 

 ing adults. The moist dog meat should be suspended by a wire basket 

 from the top of the ovipositing cage so it does not come in contact with 

 the flour in the bottom ; otherwise the flour will lump and become difficult 

 to sift. Fresh food was supplied at least once a week. Whenever moist 

 food such as meat or portions of banana was supplied the rate of ovi- 

 position increased remarkably. The increase in oviposition may be 

 due to an increased amount of water present since relatively dry dog 

 meat did not give an increase. 



With the food described and the environment maintained at 30 C. 

 and 80% relative humidity Tenebrio molitor may be reared from egg to 

 adult stage in less than 4 months. 



Family curculionidae 



THE DUCK-WEED WEEVIL, TANYSPHYRUS LEMNAE 



Minnie B. Scotland, New York State College for Teachers 



THIS very minute, widely distributed weevil is easily reared 

 wherever a culture of the common duckweed, Lemna minor, may 

 be maintained.* It is easy to collect, but often hard to find, being but 



* As in a greenhouse tank or trough filled with pond water. 



