438 INSECTA MADERENSIA. 



Fam. 39. CASSIDID^. 



Genus 145. CASSIDA. 

 Linnaeus, Syst. Nat. i. (1735). 



Corpus parvum vel mediocre, latum, rotundato-ovatum, subtus deplauatum : ore infra caput horizontale 

 sito nccnon a prostemo subtecto : prothorace et ehjtris ad latera valde explanato-jiroductis, ad 

 basin latitudine subsequalibus ; illo semicirculari, caput obtegente : alts plerumque amplis. An- 

 tennm apieem versus ]e\-iter incrassatiP, articulo primo robusto parum breviusculo, secundo brevi, 

 reliquis latitudine paulatim crescentibus (tertio ad octavum longitudine decrescentibus, octavo ad 

 ultimum crescentibus, ultimo elongato-ovato apice acuminate). Labrum corneum transverso- 

 subquadi-atum, apice duplicatum et in medio fisso-emarginatum, angulis anticis rotundato- 

 ampliatis. MandihulcE validie cornese concava; latse, apice rotundata; et fortiter subporrecto- 

 dentatae, margine intcruo integro. Maxillce biloba; membranacese : lobo externo angusto sub- 

 cylindrico subpalpiformi fere recto, apice obtuso pilisque paucis longissimis instructo : interno 

 parvo. Palpi subfiliformes ; maxillares articulo primo parvo, secundo majore subclavato, tertio 

 huic paulo bre^iorc, ultimo elongate subfusiformi apice acuto ; hihiaJes e scapis liguL-e conuatis 

 sui-gentes, articulo primo jjarvo, secundo majore crassiore, ultimo elongate subfusiformi apice 

 acuto. Mentum membranaceum minutum, apice leviter concavum. Ligula tenuissime mem- 

 branacca subovata, apice retundata pilisque longissimis aucta. Pedes breves retractiles : tarsis 

 brevibus latis (articulo tertio longissime bilobe, quartum quintumque breviusculum omuino 

 includente). 



The common genus Cassida, so universally distributed throughout the world, is 

 almost too well known to require comment. The singular outline of the insects 

 composing it, which are greatly flattened below, and have then- prothorax and 

 elj^ra expanded laterally to such an extent as to render the entire body, except 

 the tarsi and the apical half of the antennae, invisible from above, in conjimction 

 with their sluggish movements and the peculiar structure of their head (which, 

 although itself horizontal, has the mouth situated altogether beneath it), have 

 gained for them the not inappropriate name of Tortoise Beetles. This curious 

 analogy moreover with the Testiidinata is even fm-ther carried out, in some of the 

 species, from the remarkable colom- Avhich they present, the clouded (or waved) 

 fasciae and spots with which they are ornamented giving then- upper sm-face some- 

 what the appearance of tortoiseshell. They are generally found, motionless, on 

 the leaves of plants, to which their flattened under-quarters and broad feet enable 

 them to adhere very closclv ; whilst the brii?ht green hue Avhich so manv of the 

 representatives (either cntu-cly or La part) display, renders their chance of detection 

 by birds, in positions thus exposed, the less probable. Such are some of the 

 external features wliich readily separate the Cassidcs from the members of the 

 allied groups ; and yet even in obscm-er details they are scarcely less remarkable, 

 — since then- enormously bilobed thii-d tarsal joint, which completely includes (not 

 merely the minute fourth one, but also) the y?/if// articulation between its processes, 



