16 BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
upon corn. Owing to its status as a pest of millet and hops it is fre- 
quently mentioned in foreign literature as the " millet borer " and 
the "hop-vine borer." The original host of the species is a matter 
of conjecture, but it is believed by different authorities to have been 
either the hop plant or some one of the larger Asiatic or European 
grasses or grasslike plants. The fact that corn is of American 
origin precludes the possibility that this plant was the original host 
of P. nubilaiis. The insect was first found in middle Europe living 
in millet (P. miliaceum) and in maize. Judging from the known 
history and habits of the insect and the history of its more sus- 
ceptible hosts, there appear to be good reasons for considering 
wild hop as the original host. Hop affords excellent opportunities 
for the survival of the insect, since it is a perennial, whereas millet 
and hemp, two other possible original hosts, are annuals. Millet is 
said to derive its origin from Egypt and Arabia and hemp from 
Dauria and Siberia, but the hop is indigenous to Europe. 5 
De Crombrugghe de Picquendaele (13) records that in Belgium, 
mugwort (Artemisia vulgaris L.) is the chief host plant. P. Chre- 
tien, curator of the National Museum of Natural History at Paris, 
also states in correspondence that this plant is the favorite host in 
northern France. This and allied species are mentioned as hosts by 
several other writers. Pigweed (Amaranthus retroflexus L.) is re- 
corded as a frequent host by Jablonowski (29) and has been found 
commonly infested near Hyeres, France, by W. R. Thompson, of the 
Bureau of Entomology. 
Foreign literature contains reference to a great variety of occa- 
sional or minor host plants, including oats (49), barley (49), cot- 
ton (69), rice (8, pp. 39-40), kafir (8, pp. 39-40), bean pods (52), 
sunflower (36), mustard (36), barnyard grass (Echinochloa crus- 
galli (L.) Beauv.) (33) , giant reed (Arundo donax L.) (47), fuller's 
teasel (Dipsacm fullonum L.) (29), green foxtail (ChastocMoa 
viridis (L.) Scrib.) (52), stinging nettle (Urtica urens L.) (50, 
p. 16), thistles (Girsium or Carduus spp.) (29), ploughman's 
spikenard (Inula conyzaD. C.) (13), stiff inula (Inula squarrosa "L.) 
(72, p. 106), and common reed (Phragmites commMnis Trin.) (13). 
K. W. Babcock recorded an infestation in feterita at Mezohegyes, 
Hungary. 
Professor Chretien, in correspondence, mentioned thistle (Carduus 
tenuiflorus Curtis) and garden orach (Atriplex hortensis L.) as 
hosts in northern France. W. R. Thompson, in correspondence, 
has recorded bean pods, tomato fruits, tumble weed (Amaranthus 
graecizans L.), wood amaranth (Amaranthus silvestris Desf.), and 
Picris spinulosa Guss. as hosts in the vicinity of Hyeres, France, 
and he observed eggs on dock (Rumex sp.) in the Paris region. 
From Ekaterinoslaw, Russia (46), it is mentioned as a "market 
garden pest." Jablonowski 5 has cited an instance where grapevines 
(Vitis vinifera L.) Avere heavily infested by P. nubilaiis larvae 
which had migrated from near-by cornstalks. The species has also 
been found in oak galls (52). The adults have been observed upon 
heather (32) and upon virgin's bower (Clematis vitalba L.) (29), 
but there is no record of the larvae being found in these plants. 
Sand (53, p. 121) and Vuillet (72) have recorded the larvae from 
several of the Gramineae. 
See footnote 1. 
