44 The Mechanism of Byo'ltjtiost in Leptinotaesa 



BlOTYPE NIGROPtTNCTATA StUEM. 



Similar to signaticollis (plate 2, fig. 3), but with elytra having numerous 

 large black punctations, which may or may not show arrangement in pattern of 

 ten irregular double rows; punctures often confluent, giving the appearance of 

 longitudinal vittae. Appears also in experiment, most often as a dominant, and 

 when isolated breeds true; female sex-linked, but not uniformly so. (See also 

 Jacoby, 1883, p. 233, who had Sturm's specimens for study.) Recorded from 

 Cuernavaca, Cuautla, Bstado de Morelos, Atlixco, Estado de Puebla. 



MULTITitNIATA DIVISION. 

 LEPTINOTARSA MULTIT^NIATA StIl. 



Myocoryna multitwniata Stai, 1859. Ofv. af K. Vet. Ak. Forh., p. 317.4. 



Ohrysomela multitwniata Stai, 1862. Monog. Chrys. Am., p. 164. 



Leptinotarsa multitwniata Stai. Gemminger et Harold, 1874, Catalog. 

 Coleop., t. IX, pt. 1, p. 3441; Jacoby, 1883, Biol. Centr. Am., vol. VI, pt. 1, 

 p. 253; Tower, 1906, Inves. Evol. Chrys. Beetles, Gen. Lept., Carnegie 

 Inst. Wash. Pub. No. 48, pp. 7, 18. 



This species has given me more trouble in the effort to untangle its taxonomic 

 relations than all of the others combined. It is a plastic, variable, polymorphic 

 form, showing curious phenomena of heterogeneity which I shall discuss later. 

 Prom present data I have arranged the species and its minor forms as follows •. 



L. multitwniata Sta.1. 



Habitudinal variation: multitwniata StS,l. 

 Recurrent mutation : melanothorax Stai. 

 Saltation: tacuiayaensis nov. var. 

 Biotypes: 



muUilineata Stai. 

 ohscura nov. var. 

 Habitudinal variation : intermedia nov. var. 



Saltation, melanothorax Stai. 

 Habitudinal variation: variabilis nov. var. 

 Recurrent mutation : melanothorax Stai. 

 Biotypes: 



Red hypodermal color. 

 Orange hypodermal color. 

 Yellow hypodermal color. 

 "White hypodermal color. 



Habitudinal vabiety L. multit^niata-multit^niata SxAii. 



Stal's description of the typical muUitwniata form, taken from his monograph 

 (1863), is as follows: 



" Ovalis, supra flavescens, subtus cum antennis, pedibus, maculis prothoracis, 

 limbo scutelli, sutura vittisque quinque, exteriore intramarginali, elytroruni, 

 nigra; maculis pectoris limboque apicali segmentorum ventris flavis; elytris 

 minus regulariter seriatim punctatis. Long. 10, Lat. 6f milUm. 



" Patria: Mexico (Mus. Berol., Coll. Dohrn). 



" G. muUilineata simillima, prothorace latiore, elytris regularius seriatim 

 punctatis differt. Ovalis, sat convexa, nigra, nitida. Caput sat dense, distincte 

 punctatum, vittis duabus obliquis, basi conjunctis, flavis. Antennae articulis 

 quinque apicalibus transversis, clavam sat distinctam formantibus. Prothorax 

 elytris nonnihil angustior, sat convexus, antrorsum sensim, angustatus, disco 

 parce, subtiliter, utrimque densius, subfortiter punctatus, flavescens, maculis 

 compluribus lateralibus lituraque media ut littera V formata, plus minus con- 

 fluentibus, nigris ornatus. Scutellum flavescens, plus minus late nigro-limba- 



