INSECT ENEMIES OF EASTERN FORESTS 973 
KEY TO THE MORE IMPORTANT LARVAL GROUPS OF THE CHRYSOMELIDAE 21 
iL. eate Miners sams 2 pane ttt aes Se ce oeteta es WR ec APL ee 2 
Hxternaleteeders: legs; wellideveloped=- 2 2-_--so2 2.) ) Se 3 
2. Legless, ninth abdominal segment terminal: 
Feeds in JOO) OY C2 Sh cig actin ate I A pat oe ee Zeugophora 
Reedspmebirchess oak nazelmes= sn Leal. |e Syneta 
Legs present, eighth abdominal segment terminal: 
eed saimelocustsese: Serato ee ee ee Chalepus 
Feeds chiefly in basswood, sometimes oak________ Baliosus 
3. Larva enclosed in a case; head flat on dorsal surface, acting as a lid 
: to case___ Coscinoptera, Pachybrachis, Cryptocephalus, Bassareus 
Larva usually not in a case; head not flat on dorsal Suriaces=2 22" ae 
4, Tarsi long, slender, without pad, usually no ocelli 
Xanthonia, Glyptoscelis, Tymnes, Nodonota, Colaspis 
Tarsi short, curved, usually with a pad 
Diabrotica, Galerucella, Blepharida, Altica, Calligrapha, Plagi- 
odera, Chrysomela 
DISCUSSION OF THE CHRYSOMELID BEETLES 
ZLeugophora scutellaris Suftr., the cottonwood leaf-mining beetle, 
according to Strickland (399) is a European species. Cottonwood 
and other poplars are attacked, and, although the insect is not often 
injurious, it is at times so abundant that ‘trees are completely de- 
foliated. The adults are about 3 to 4 mm. in length. The coarsely 
punctuate elytra and abdomen are black and the remainder of the body 
yellow. The adult skeletonizes the lower surface of the foliage, pre- 
ferring the first leaves that appear. After feeding for a short time, the 
females lay their eggs singly in small punctures in the lower surface of 
the leaves. The larvae mine in the soft inner tissue, chiefly against the 
upper surface. They are solitary in their feeding habits, and when 
there are two or more mines in a leaf they are usually completely sepa- 
rated. If several mines join, only one larva usually survives. The 
full-grown larvae vacate the mines, drop to the ground, and prepare 
small, oval, earthen cells below the surface, where they pupate. The 
combined feeding of adults and larvae often causes complete defolia- 
tion. The beetle is found from New York and New Jersey west to 
Montana and south to New Mexico. 
Colaspis pint Barber, the pine colaspis, is an elongate, oval, convex 
beetle about 5 mm. in length, rusty yellow or brown, with faint greenish 
reflections. The adults damage the 1l-year-old needles of pine repro- 
duction and occasionally older trees by irregularly chewing the edges 
in to the midrib, causing the ends of the needles to turn brown, but 
leaving the bases green. Later, with heavy feeding, the entire needle 
may be destroyed. The damage occurs locally throughout the Gulf 
States in small areas up to 10 acres. From a distance the damage 
appears as though fire had swept through the stand or reproduction 
field, but a close inspection reveals that only the needles on the tops of 
the trees are dead. The damage occurs on both high and low ground. 
Heavy feeding, especially on poor soil, checks the growth of trees, but 
it is doubtful if permanent injury results. Plantations of young pine 
21 Many of these larvae are imperfectly known and poorly represented in avail- 
able collections. It is impractical, with the material at hand, to carry this key 
down to species. 
