H. C. Severin.
A Gynandromorph of Melanoplus mexicanus mexicanus (Saussure) Extreme Migratory Phase (Orthoptera: Acrididae).
Psyche 62:104-107, 1955.

Full text (searchable PDF, 360K)
Durable link: http://psyche.entclub.org/62/62-104.html

The following unprocessed text is extracted from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

A GYNANDROMORRH OF
MELANOPLUS MEXICANUS MEXICANUS
(SAUSlSURE) EXTREME MIGRATORY PHASE
'ORTHOPTERA : ACRCDIDAE)
8outh Dakota State College, Brookings, Bouth Dakota The gynandromorph described in this paper was loaned the author by Dr. Roscoe E, Hill, Chairman of the De- partment of Entomology, University of Nebraska. The specimen was taken from the collections of the University of Nebraska [State Museum and was returned to the Muse- um of that University. The specimen was collected at or near Pine Ridge, Nebraskay in July. No further definite data regarding the origin of the specimen was available such as year when the specimen was collected or the name of the collector. For purposes of comparison the author of this paper borrowed from the Nebraska State Museum thro~~gh Dr. Hill a normal male and a normal female speci- men of Melanoplus mexicanus mexicanus (Saussure) Extreme Migratory Phase. 'These specimens were collected at or near West Point, Nebraska. Neither of these speci- mens had a date label attached to them but one of the specimens had a label attached to it with the following data printed in inky by hand: Melanoplus spretus Thos. (Det. L. Bruner).
Since the gynandromorph and the borrowed male and female grasshoppers were apparently old, it is reasonable to believe that Professor L. Bruner might have been the collector not only of the normal grasshopper but of the 'Approved for publication by the Director of the South Dakota Agri- cultural Experiment Station as Journal Series No, 322. EXPLANATION OF PLATE 10
1. Dorsal view of posterior part of abdomen; 2. lateral aspect of right side of posterior part of abdomen; 3. ventral view of posterior part of abdomen. C. cereus; EG, egg guide; I?, furculum; RDV, right dorsal valve of ovipositor; RW, right ventral valve of ~~ipositor; SA, supra-anal plate; SG, subgenital plate; W, margin of tegmen.



================================================================================

SEVERIN - MEL- NOP PLUS MEXICANUS MEXICANUS



================================================================================

106 Psyche [September
gynandromorph as well.
The author wishes to thank Dr.
Hill for the privilege of studying the grasshoppers loaned him.
Melanoplus mexicanus phase spretus (Walsh) is re- garded by most entomologists as a phase of Melanoplus mexicanus mexicanus (lSaussure) and is looked upon by most Orthopterists as the Rocky Mountain Locust which was so prevalent and destructive in the United States from 1862 to 1876.
The author of this paper described a gynandromorph of Melanoplus mexicanus mexicanus (S~USS.)~ but this de- scription of the morphology is quite different from the? description of the gynandromorph of M. m. mexicanus (Sauss.) Extreme Migratorv Phase presently to {be de- scrjbed.
Description 'of the
Gynandromorph of M. m. mexicanus (Sauss.) Extreme Migratory Phase.
This gynandromorph is typically female in structure in- cluding the body morphology and the appendages except for the posterior end of the abdomen which is typically male in the left half and mostly typically female in the right half. The lateral carinae of the fastigium of the head, are not prominent and the fastigeal depression is shallow. These characters are typical of normal female specimens. The interocular space is wide as in normal female speci- mens.
The tubercle on the mesosternum, which is very well developed in normal male specimens and only faintly in- dicated or entirely absent in normal females, is lacking in the gynandromorph.
The femora and tibiae of the first
two pairs of legs of the gynandromorph are less heavily constructed than in the normal males and in this respect resemble the femora and tibiae of typical females. The
arolia of the tarsi of the gynandromorph are small and resemble those of a normal female.
'The left half of the posterior end of the abdomen is typically male in structure with very little distortion. The 2Severin, H. C. 1943. A Study of a Gynandromorph of Melanoplus mexicanus mexicanus (Sauss.) (Orthoptera) 1943. Journal of New Yosic Entomological Society Vol. LI., pp 179-183.



================================================================================

right half, however, is female with some distortion. A normal appearing upper and lower valve of an ovipositor are present on the right side. The right cercus is female in shape, while the left resembles the cercus of a male. The furculum on the left side is absent while on the right it is present and resembles in size and shape the furculum of the typical male. The supra-anal plate is bilaterally symmetrical and resembles rather closely the supra-anal plate of a male except for a transverse ridge extending across the right half of it. A subgenital plate is present but only the left half is developed. Consequently the ter- minal notch present in normal males is lacking in this gynandromorph. On the right side a terminal abdominal sternite resembling one-half of the end sternite of a fe- male abdomen is present. Even one-half of the so-called egg-guide terminates this sternite (see figures I, 2, 3).



================================================================================