133 



The insect which forms the subject of this paper is Toxotry- 

 pana ciirvicauda, Gerstaecker. It was first broug-ht to the notice 

 of the U. S. Department of Agriculture in 1905, when it was 

 bred from a maggot-infested papaw fruit, from the subtropical 

 plant introduction field station at Miami, Florida. Snice that 

 time, the increasing importance of the papaw as a possible com- 

 mercial crop has led to investigations in connection with this 

 insect. 



The papaw fruit fiy is now recorded as occurring in the south- 

 ern part of Florida, in Costa Rica, Yucatan, Brazil, Peru, Porto 

 Rico, Bahamas, and St. Jean ( ? St. Jan ) Danish West Indies. 

 It is stated that this last record has been erroneously given at St. 

 John, Antigua. 



Description— The adult papaw fruit fly (To.vofrypaiia ciirz'i- 

 caitda) belongs to the dipterous family Trypetidae and exhibits a 

 certain superficial resemblance to a common brown wasp (Po- 

 listes). This is due not only to its snnilarity of size, form, and 

 general coloration, but in life this is accentuated by the manner 

 in which it walks about on the fruit, wdth its body well elevated 

 upon its slender legs, and by a certain nervousness of movement. 

 The female is remarkable for its long and slender curved oviposi- 

 tor, which exceeds the length of its body. 



The egg. The eggs were procured from gravid females by 

 dissection. The number of eggs produced by a single female 

 appears to be slightly in excess of 100; the counts from two 

 females, both showing a distended abdomen and probably contain- 

 ing a nearly full complement of eggs, gave 103 fully developed 

 eggs in each case. No eggs in process of development were 

 present, which indicates that all the eggs are disposed of within 

 a short period. 



The larva. The larvae are shining, dirty, greenish white in 

 color while feeding^ upon the interior seed mass. Larvae that 

 have matured within the ripened fruit, and that have penetrated 

 into the meat, are the same rich golden yellow color as the ripe 

 fruit. 



Habits of the larvae. The larvae of the papaw fruit fly occur 

 in the interior of the fruit, first feeding in the central seed mass, 

 but later, as they mature and the fruit ripens, working into the 

 meat and ruining the fruit. The number of larvae in a single 

 fruit varies from two or three to twenty or more. Sometimes.' 

 larvae of diflferent sizes occur in the same fruit at the same time, 

 showing that the infestation was from more than one oviposition. 



Cultivated fruit has been found to be generally less infested 

 than that growing wild, and this is ascribed to the fact that the 

 flesh of the cultivated fruits is usually thicker, the thin-fleshed 

 varieties appearing to be more generally attacked. It seems that 

 the eggs are deposited inside the seed cavity, or at least the in- 

 sects develop best when this happens. Thick-fleshed fruit often 



