68 The Mechanism of Evolution in Leptinotarsa 



Third larval stage: Like L. juncta, smaller, paler (see Townsend, Trans. Tex. 

 Acad. Soe., vol. 5, pp. 51-101). Length at end of stage, 8 to 14 mm. (Plate 7, 

 fig. 6.) 



Length of larval life: 15 to 30 days; average 22 days. 



Pupa: Pupates 1 to 3 inches below surface of ground. Pupa pale yellow. 

 Pupation lasts 10 to 20 days ; average 1-4 days. 



Length of ontogeny: 30 to 60 days; average 50 days. 



Geogkaphicax Distribution. 



Eio Grande Valley in Texas and northern Mexico; possibly northward into 

 the valleys of Eed and Arkansas Rivers. I have one specimen labeled Pueblo, 

 and to this has been added Colorado, but I have no confidence in the correctness 

 of the locality. Accurate records : Dallas, Brownsville ( Sch. ) , Laredo, Corpus 

 Christi, Fort Worth, Santa Tomas, San Antonio, Texas; Matamoros, Rosita, 

 Ciudad, Porfirio Diaz, Mexico. 



Habitat, ecology, life-history: In cultures this form has always given two 

 generations per year — one early in the season, then a long wait and one late in 

 the season, then hibernation through the winter. In nature I suspect that this 

 is also its behavior, but I have not had opportunity to fully verify this point. 

 It is also probably variable in behavior in nature. 



Leptinotarsa tumamoca nov. sf. 



Description of Living Animals. 



(Plate 7, fig. 8.) 



Imago: In shape, general color, and pattern much like L. texana, but only 

 half the size. Above: Oval, convex, epicranium and pronotum light yellow- 

 brown marked with black; epicranium strongly and densely punctate on sides 

 and posterior portions, center polished, few small or no punctations present. 

 Pronotum densely punctate on lateral portions; center and posterior margins 

 smooth, often polished; eyes black, pattern on epicranium lacking, or anterior 

 lateral epicranial spots showing only a trace thereof ; pronotal pattern, /' and / 

 almost always absent, as are am and pm, a' and a never fused, but &' and h almost 

 always fused with a' and a; scutellum dark brown, polished ; elytra, ivory-white 

 or yellowish ivory-white; anal edge yellowed or brown (cubital and anal stripes 

 lacking), medials present, well developed ; ramous and anterior subcostal always 

 united posteriorly and posterior subcostal often united to anterior subcostal at 

 or anterior to its junction with the ramous; costal stripe bent, shortened pos- 

 teriorly, all edged with regular single row of punctations. Costal edge inflexed, 

 smooth, flat, yellow. Below : All parts uniform pale yellow, edges of sclerites 

 and joints sometimes brownish, anteunEe and terminal joints slightly darker, 

 no pattern on thorax or abdominal segments. 



Size: Smallest member of group and possibly of the genus; is not larger and 

 probably averages smaller than L. lineolata. 



Sexes: Female, sternal sclerite of last abdominal segment rounded, flat, 

 smooth; male with same sclerite truncate, slightly grooved. Male slightly 

 broader and larger than female. 



Juvenile Stages. 



Eggs: Small, oval, ends squared, not stalked, laid on lower surface of leaves 

 singly or in small bunches of 10 to 20; pale bluish-yellow or yellow; 1.25 to 

 2 mm. long, 0.6 to 1 mm. broad. Incubation lasts from 5 to 10 days; average 

 6 or 7 days. 



