June, 1896.] Webster: North American Species of Diabrotica. 
67 
THE PROBABLE ORIGIN AND DIFFUSION OF 
NORTH AMERICAN SPECIES OF THE 
GENUS DIABROTICA.—II. 
By F. M. Webster. 
Since the publication of my paper in No. 4, Vol. Ill, of the Jour¬ 
nal, a considerable amount of information relative to the subject has 
since either been communicated to me, or placed at my disposal where I 
did not before feel at liberty to use in print. I have, therefore, thought 
best to add this supplementary note, including in it a few correc¬ 
tions. 
Professor Cockerell has very kindly prepared the following table 
illustrating the position of his D. vittata var. incerta , Ckll. found 
by him from Mesilla Valley southward to Juarez, Mexico, opposite El 
Paso, Texas, on the Rio Grande: 
A. Antennae with the three basal joint pale. 
a. “ Legs yellow, the knees, anterior tibiae and tarsi, and the tips of the middle 
and posterior tibiae and their tarsi, piceous.” (Horn). vittata Fab. 
b. Legs more or less darkened, but basal third of anterior femora, and basal 
two-thirds of middle and posterior femora, and hind tibiae more or less in mid¬ 
dle, yellow. vittata var. incerta Ckll. 
B. Antennae all black. Legs all black except bases of femora, trivittata Mann. 
In regard to the distribution of these in the valley of the Rio 
Grande, Prof. Cockerell gives me the following table: 
000 ft I ^ anta Fe, D. 12-punctata , (1 specimen not taken by himself). 
( Gallinas Canon, D. atripennis , (reported by the Snow party). 
*5,000 “ Albuquerque, 
*5,000 “ Socorro, 
3,000 “ Mesilla Valley, 
D. longicornis. 
D. 12-punctata , . . D. lemniscata. Collected by Prof. 
YVickham, at Alberquerque. 
or 
_ 6 ( 
T . ) D. tricincta. 
Juarez, Mexico, - _ 
j D. vittata var. incerta , 
The occurrence at Gallinas Canon should have been credited to 
Prof. Snow and not to Prof. Cockerell. Prof. Wickham calls my at¬ 
tention to the fact of Dr. Horn’s having observed a close resemblance 
between Andrector 6 -punctatalAoTn, and Diabrotica 12-punctata Oliv., 
while he had himself confused a second species of Andrector with 
Diabrotica tricincta Say, and placed them in his collection as all be- 
* These records of elevations are supplied by myself and taken from surveys 
made by the U. S. Geological Survey and published in 1890. The elevation of 
Juarez, Mex., opposite El Paso, Tex., is but little less than 3,800 ft. 
