﻿322 POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



a bare mention of it in a recent bulletin, "Diseases and Pests of the Orange in 

 Mexico," published by the Departmento de Fomento in Mexico City. 



While carrying on the regular work of the Pomona College Mexican Ex- 

 pedition during the past summer, an excellent opportunity was afforded for 

 determining the distribution of this fly in many parts of Mexico. In a map 

 showing the distribution, published by Mr. Isaac in his report, the pest is said 

 to exist in the following localities : Morelos, Acapulco and a large part of the 

 State of Guerrero, northwestern portion of Oaxaca, Vera Cruz and Tampico. 

 He gives the following places as probably infested : Chiapas, parts of 

 Campeche and Yucatan, southern end of the State of \'era Cruz and parts of 

 Puebla. The maggots and flies were found this year in Chiapas in several 

 localities ; they are also present in the fruit districts of Cordova, Oaxaca, 

 Jalapa and Colima. It is a curious fact that the native inhabitants of a place 

 almost invariably say that the orange worm does not exist in that place, or 

 if it is perfectly patent that it does exist, they try to minimize the effect 

 of its presence as much as possible. I was told, for instance, by several fruit 

 growers of Jalapa that the pest was unknown to that region ; but it was 

 found in abundance within a few miles of the cit\- at Coatepec, a great fruit 

 producing center. The presence of the worm in Colima was not mentioned 

 by Mr. Isaac, but my native assistant, a long-time resident of that place, 

 informed me that oranges and mangoes there have for many years been 

 infested with it. As this is near to the growing shipping center of Manzanillo, 

 the danger to California from this source is apt to be as great as from 

 Acapulco if the present precautions were not continued. In addition to the 

 places mentioned, the fly was found in more or less abundance in many of 

 the localities recorded by Mr. Isaac. This shows that the pest is apparently 

 on the increase and is becoming more widely distributed each year. It has 

 been claimed repeatedly that this insect is peculiar to the tierra caliente, or 

 hot lands, of Mexico, but its presence in the higher subtemperate lands would 

 tend to show that it can and may adapt itself to the cooler climatic conditions. 



Perhaps a brief description of the insect and its immature forms and an 

 explanation of its method of injuring the fruit would not be out of place 

 here. The fly is one member of a large group of fruit-frequenting flies, 

 formerly all classed in one genus, Trypeta. This species is distinct from the 

 rest in the coloration of the wings and especially in the long tube-like abdomen 

 of the female. Across its outstretched wings the fly measures about three- 

 quarters of an inch ; the body of the female is very nearly half an inch in 

 length ; the male is shorter owing to the absence of the long tube present on 

 the female abdomen. It is orange yellow in general color; its wings are quite 

 clear except several yellowish brown stripes and blotches as shown in the 

 illustration (Fig. 120.) 



Its movements are very slow and delilierate ; it prefers to stay on the 

 fruit or under side of a leaf near to some fruit ; when disturbed, it usually 

 flies to another orange not far away. During the time of oviposition by the 

 female she walks very slowly over the surface of the orange or mango for a 



