34 BULLETIN 743, U. S. DEPARTMENT OV AGRICULTURE. 



have insect enemies : it is merely stating that the tree seems to be less 

 seriously affected by parasitic insects than citrus trees under the same 

 environmental conditions. v 



One insect stands out above all others observed in Guatemala, both 

 for the damage which it occasions and the apparent difficulty of con- 

 trolling it. This is a small brownish gray weevil {C onotrachelus 

 n. sp. 1 ), whose larvae are found sometimes in mature avocados pur- 

 chased in the markets. 



No external evidence of its presence is noticeable (at least to the 

 unskilled observer), but on cutting the fruit in half the seed is 

 found to be more or less riddled with large, round tunnels (PL XI), 

 and 1 to 10 or more fat, wriggling larvae, varying from white to 

 pinkish in color, greet the eye. While the larvae are rarely seen 

 working in the flesh itself, they often burrow along the outside of 

 the seed in contact with the flesh, discoloring the latter with their 

 brownish powdery castings. In some avocados examined the seed 

 had been so thoroughly honeycombed that it was reduced almost to 

 powder. 



Needless to state, a fruit attacked by this insect is rendered prac- 

 tically unfit for use. Even though the flesh itself may not have been 

 damaged, the sight of the white larvae and their tunnels in the seed 

 is sufficient to nauseate any housewife. The widely known Mediter- 

 ranean fruit fly (Ceratitis capitata) produces no more disgusting 

 results than this insect. 



The distribution of this weevil in Guatemala seems to be wide. It 

 was found from El Eancho on the eastern slope to Mazatenango on 

 the western, and from Antigua in central Guatemala to the Vera Paz 

 district in the north. The lowest elevation at which it was found 

 was about 1,000 feet, the highest 5,300. It was seen most abundantty 

 at Panajachel, where most of the fruits offered in the market in early 

 January, 1917, were found to be infested. Little is known of its life 

 history. The larva is about one-half inch long, with a brown head 

 and 12 white segments composing its body. After tunneling in the 

 fruit it works out through the skin and drops to the ground, where 

 it pupates, the mature weevil emerging some days later. Nothing 

 has been learned with regard to the habits of the adult. 



Next to this insect, which easily outranks all others in destructive- 

 ness, as far as was observed during the course of a year's work in 

 Guatemala, among the most troublesome pests are gall-making psyl- 

 lids, 2 which are abundant in the Antigua region and fairly common 

 in several others. Probably more than one species are represented. 

 These insects produce elongated conical galls which stand erect on the 

 upper surfaces of the leaves. They are sometimes so thickly placed 



1 This species is described by H. S. Barber (Proc. Ent. Soc. Wash. ; in press). 



2 Probably Trioza koebelei Kirkaldy.' 



