486 



life-cycles varying from 35 to 44 days. The various generations 

 overlap and all stages of the insect are found abundantly at the same 

 time. Parasites of P. periusalis include two unidentified Hymenoptera 

 infesting the eggs. Numerous individuals of the Tachinid, Argi/rophylax 

 alhincisa, Wied., were reared from larA^ae collected in the field. The 

 Ichneumonid, Chleomis sp., was also frequently found parasitising 

 the larvae, and numbers of a small Braconid were reared from the 

 pupae. As the damage is done chiefly w^hen tobacco is young, it 

 comes at a time when most growers are dusting the plants with 

 arsenicals against flea-beetles, and this is a sufficient remedial measure. 

 All wild host-plants growing near tobacco fields should be destroyed, 

 especially the wild egg-plant, Solanum torvum. 



Dicyphus luridus, Gibson, has only recently been described [see 

 this Reirieiv, Ser. A, vi, p. 130]. This is a Capsid bug closely related 

 to D. minimus, Uhler, which does great damage to tobacco in Florida. 

 It is as yet known only in Porto Rico, where it feeds chiefly on tobacco ; 

 it is not uncommon on tomatoes in g^-rdens and lives on related wild 

 Solanaceous plants, occurring abundantly on the weed, Jafropha 

 gossypifolia. The eggs are inserted singly in the midrib of the tobacco 

 leaf, and hatch in 6 to 10 days, the young nymphs beginning at once 

 to suck the sap from the leaves. Like other Capsids, these insects 

 occasionally feed upon others, sucking the body juices of any that 

 get caught on the sticky foliage of the tobacco leaves. There are 5 

 nymphal stages of 3-G days each, the total life-cycle averaging about 

 30 days. The damage done by this insect in Porto Roco has not 

 as yet been serious, and if the ground is kept free from the weeds that 

 harbour it, no further control measure should be necessary. Dicyphus 

 prasinus, Gibson, also a recently described species [loc. cit.~\ is very 

 similar to D. luridus, but is rather less abundant on tobacco and 

 and rather more frequently found on tomato. The life-histories 

 of the two species and the damage done to tobacco are practically 

 identical. 



Vegetable pests have given considerable trouble during the year 

 and a bulletin describing these is in course of preparation. Plutella 

 maculipennis (diamond-back moth) has been very abundant, the larvae 

 damaging cabbage leaves. A spray of 3 lb. lead arsenate to 50 U.S. 

 gals, water is an efficient control if used regularly ; if the caterpillars 

 become very numerous, they should be destroyed by spraying with 

 kerosene emulsion. 



The usual citrus pests occurred dm'ing the year. Damage to the 

 fruit by red spiders and rust mites can be avoided by spraying the 

 trees, as soon as the mites appear, with lime-sulphur 1 : 50 or 1 : 75, 

 with the addition of flour paste, using 4 lb. flour to each 100 U.S. gals, 

 of spray. Diaprepes spengleri, which destroys the foliage of citrus 

 trees, frequently congregates in large numbers in restricted sections 

 of a citrus grove and can then be collected by shaking the weevils 

 from the trees into strips of canvas. When they occur uniformly 

 throughout a grove, a spray of 5 lb. lead arsenate to 50 U.S. gals, 

 water should be used. Solenopsis geminata (brown ant) forms nests 

 at the base of young citrus trees and chews the tender young branches, 

 frequently causing them to die. The nests should be thoroughly 

 sprayed on two consecutive days with | lb. caustic potash or fish-oil 

 soap dissolved in water, with the addition of 1 pint crude carbolic 



