208 THE MONTHLY BULLETIN, 



NOTES ON THE LIFE HISTORY OF A SPECIES OF WASP- 

 LIKE PARASITES OF THE GENUS LEPTOMAS- 

 TIX, PARASITIC ON THE MEALY BUG. 



By Henry L. Viereck. 



The genus Leptomastix was published by Foerster in 1856, but no 

 species was included under this name until 1875, when Mayr pub- 

 lished the description of the first species and genotype under the name 

 of Leptomastix histrio. Of this species nothing more is known than 

 that it came from Italy. In 1885. the second species was described 

 by Howard under the name of L. (lactjilopii. This species is known to 

 occur in Washington, D. C. and in Grenada, West Indies, and is 

 recorded as a parasite of the citrus mealy bug [Psevdococcus citri 

 (Risso.) ]. The third species was described by Ashmead in 1887, under 

 the name of L. tincavora from Florida and is on record as a parasite 

 of Andricus pattoni Bassett. 



The species here considered appears to be new to science. 



The species of the genus Leptomastix are Chalcis flies of the family 

 Encyrtidae. 



LEPTOMASTIX SP. 



In June, 1914, in the suburbs of Palermo, Sicily, Italy, the writer 

 noticed some parasites, with banded wings, that were walking over 

 ovipositing Pseudococcus citri. The manifest interest on the part o 

 these parasites in the mealy bugs led to the belief that they ■were para 

 sites of the mealy biig. Quantities of mealy bug material were accord- 

 ingly shipped to the Sta.te Insectary throughout the summer months 

 of July and August. From this material parasites were bred in Sacra- 

 mento at the State Insectary. The parasites were tried out and proved 

 to be primary parasites ot Pseudococcus citri. The fact that this para- 

 site with banded wings proved to be a primary parasite of Psendococcic^ 

 citri and new to California led to an attempt at breeding it under 

 laboratory conditions on lemons infested with Pseudococcus citri. This 

 attempt was so successful that by December the original stock had 

 multiplied manifold. 



The temperature of the laboratory ranged from 50 degrees to 105 

 degrees F. The humidity was maintained by evaporating w^ater in 

 shallow pans over radiators and by means of moist moss in the cages. 



Cages made of wooden frames, cheese cloth and glass and provided 

 with shelves as shown in Figure 36, are used for breeding colonies. 

 On the shelves are placed earthenware saucers lined with moss. In 

 these moss-lined saucers are placed the lemons infested with Pseudo- 

 coccus citri. The moss is watered from time to time to keep the lemons 

 from drying up too fast. The two shelves are used so that the deterio- 

 rated lemons can be transferred from the top shelf to the lower and 

 finally be emptied into the bottom of the cage, the spoiled lemons 

 being replaced with fresh lemons. The capacity of these saucers is 

 100 to 125 lemons. Seven of these cages containing on an average 

 150 lemons at any one time yield at least 5,000 parasites a week. 



From the large cages specimens collected at random were transferred 

 to lamp chimney cages for life history investigation purposes. These 



