MEDITERRANEAN FRUIT FLY IN HAWAII. 



85 



femora, but the tibiae and tarsi are more yellowish. Length of body, 

 about 2 mm. For the original description see Bolletino del Labora- 

 torio di Zoologia, Portici, volume 9, page 374 (1914-15). 



Egg. — The egg is pure white, about 0.11 mm. long, and shaped as 

 shown in figure 17, d. 



Larva. — The well-grown larva is white and grub-like, about 1.8 

 mm. long (fig. 17, a). When viewed from above, spiracles are evident 

 on segments 3-9 (fig. 17, h). The mandibles are microscopic (fig. 

 17, c). When first hatched, larvae are about 0.28 to 0.3 mm. long. 



Pupa. — The pupa is about 1.9 mm. long. (See fig. 18.) 



BIOLOGY. 



Silvestri was unable to keep adults of giffardii (or giffardianus ?) 

 alive for more than 15 days. His original statement that the female 

 deposits her eggs within the eggs or young larva of 

 the host has been proved by Fullaway and the 

 writers to be incorrect. Oviposition by T. giffardi- 

 anus occurs largely in the well-grown larvae as in 

 the case of the Opiinae. The adult parasite will 

 enter larval chambers and breaks in the host fruit 

 in search of fruit-fly larvae as has been proved by 

 the writers under laboratory conditions, and accu- 

 mulating data seem to indicate that adults oviposit 

 for the most part in larvae within fruit already 

 fallen to the ground. Adults are capable of begin- 

 ning oviposition as soon as they emerge from the 

 puparium of the host. The female does not neces- 

 sarily make a new puncture in the epidermis of its 

 host for each egg deposited; in one instance 41 eggs 

 were deposited through 17 punctures. When the 

 female comes upon a larva within a larval channel 

 she deposits her eggs at points about its posterior 

 portion, but when access to the larva can be had 

 through a thin membrane of the host fruit, she may 

 deposit her eggs in any portion of the body. The punctures in the 

 epidermis are evident as small dark brown depressions. Of a total 

 of 322 adults reared from 20 pupae, 194 were females and 128 were 

 males; the number of adults reared from single pupae varied from 1 

 to 35. 



When the temperature ranges between 66° and 82° F., with a mean 

 of about 74° F., eggs hatch in about 3 days, the larvae become full 

 grown in about 8 days, and the pupae yield adults in from 11 to 15 

 days. 



Fig. 18.— Tetrastichus 

 giffardianus: Lat- 

 eral view of pupa. 

 Normal length, 1.9 

 mm. (Original.) 



