36 



PRELIMINARY REPORT ON ALFALFA WEEVIL. 



The disposal and management of this species did not differ from that 

 followed with the preceding, except that some of them were received 

 too late in the season to use in the low valleys because the majority 

 of the eggs of the weevil had already hatched. Owing to this the 

 parasites were taken to places in higher elevations 

 where eggs of Phytonomus were stiU abundant. 

 Approximately 460 were placed in field cages like 

 those previously mentioned and treated in the 

 same way. 



Mr. Fiske found this species to be very effective in 

 controlling the alfalfa weevil in Italy. 



Parasites of Larv.e and Pup.e. 



The parasites of the larva? and pupae of the alfalfa 

 weevil, which were five in number, did not appear in 

 the earlier consignments from Italy and were confined 

 pteromaiid egg to the last three received at Salt Lake City May 16 

 e w°eevii e t0 J une 3- In these three shipments were metal 



Greatly enlarged, boxes (PL X, fig. 2), wllicll included Olllv the COCOOUS 



of the alfalfa weevil. These boxes were especially 

 devised to guard against the accidental escape of adult insects of 

 any species en route. 



After being removed from the boxes in which the cocoons were 

 received, they were placed in parasite boxes of the larger type 

 (PI. XL fig. 3), where the parasites emerged and were 

 separated from the weevils that had developed en route. 

 Both weevils and parasites on emerging from the cocoons 

 in the box would seek the light and appear in the glass 

 tubes shown in the illustration, where they were readily 

 separated and the weevils killed. The parasites were 

 then transferred to glass cages (PL XL figs. 1. 4) which 

 had been previously well stocked with larvae and cocoons. 



PTEROMALID LARVAL PARASITE. 



A pteromaiid parasite of alfalfa weevil larvae (fig. 19, 

 female; fig. 20, male) was received in only the later fig. is.— Pupa 

 consignments. Thus far it has not been possible to deter- 

 mine the species. In the laboratory rearings, preparatory 

 to placing the parasites in the field cages, and later, the 

 species was carried through five generations. (Fig. 21. a 

 shows the pupa of the alfalfa weevil, with the egg (fig. 21, b) 

 asit is placed on the pupa; fig. 22 shows the larva, and fig. 

 23 shows it destroying the pupa of the alfalfa weevil; fig. 24 shows the 

 pupa of the parasite itself.) In order to accomplish this, however, it 

 was necessary to secure weevil larvae, as hosts for them, from high 



of ptero- 

 maiid egg 

 parasite o f 

 t h e alfalfa 

 wee v i 1 . 

 Greatly en- 

 1 a r g e d . 

 (Original.) 



