35 



prietor of the Susquehanna farm in St. Marys County, Md., stated 

 that during that year he had 600 acres of peas and the crop was badly 

 infested by this pea louse, which destroyed 80 per cent, of his crop. 

 This loss was a very serious matter, as our correspondent raised no 

 other crops except peaches. 



A large proportion of the identifications of the material received 

 were made by Mr. Theodore Pergande, who has also kindly criticised 

 the accompanying illustration of this plant-louse. 



THE SPECIES DESCRIBED. 



The species was described by Professor Johnson in the February 

 number of the Canadian Entomologist of the current year (Vol. XXXII, 

 pp. 56-60) under the name JVectarophora destructor. Attention is 

 called in that article to the preoccupation of the genus Siphonophora 

 both in the Myriapoda and Hydrozoa, for which reason Nectarophora 

 of Oestlund is substituted. 



This plant-louse is one of unusual size among those found infesting 

 garden plants, the average length of the body being about -1.5 mm., and 

 the total wing expanse about 11 mm. The general color of both the 

 winged and apterous forms is uniform pea-green, the same color as the 

 insect's favorite food plant. The eyes are prominent and reddish 

 brown in color. The antenna? are lighter than the body and tubercles 

 prominent; joints darker than rest of segments; seventh joint quite 

 filiform and fuscous. The legs are long and conspicuous; tarsi, distal 

 ends of tibia?, and femora fuscous. The nectaries are fuscous at the 

 apices, otherwise concolorous with the body. 



A typical winged female of this insect is shown in figure 9 with 

 wings expanded, showing venation at a, and a lateral view of the same 

 with wings folded in their natural position when the insect is at rest 

 or feeding is presented at h. At c an apterous or winged insect is 

 shown, and d shows the nymph in its last stage. The structure of the 

 third antennal joint of the winged form may be seen at e, highly 

 magnified. 



THE QUESTION OF ALTERNATE FOOD PLANTS. 



An effort was made by Mr. Pergande to ascertain if any common 

 species of weeds that were found growing late in October and early in 

 November could be alternate food plants of this insect, but with nega- 

 tive results. The plants upon which the insects were placed, but 

 which they deserted, were Sonchm aspe?\ dandelion, shepherd's purse, 

 Sisymbri ' a in officinale, and dock. 



Throughout the months of November and December, 1899, this or a 

 related plant-louse was observed and is still to be seen on the Depart- 

 ment of Agriculture grounds, feeding upon different species of vetches 

 ( Vicia villosa, gigantea, Ivdovieiana, et al.) on the experimental plats of 



