Morfologia della larva matura in alcuni Pselafidi (Coleoptera)

Abstract

LAST-INSTAR LARVA MORPHOLOGY IN SOME PSELAPHIDS (COLEOPTERA)

Last-instar larvae of 8 species (8 genera, 5 tribes), obtained in most cases in laboratory condi- tions, are described and illustrated.

Their interspecific variability was found very large , and especially it concerns characters of anten- nae, exserrile head organs and ninth abdorrrinal segment.

Examples of particular characteristics in each larval form:

- Euplectus sp., absence of the exsertile head organs, absence of the apodems of the occipital orifice, position of the head glandular pores;

- Trimium minimum, shape of the exsertile head organs, sensory lobe of amennae and ninth abdominal segment;

- Pseudozibus crassipes, shape of the exsertile head organs, mandibles and ninth abdominal segment ;

- Batrùodes oculatus, length of the last segment of maxillary palpi , spiracles of the abdominal segments 5-8 replaced by exsertile organs;

Thychobythinus glabratus, tenth abdominal segment visible in dorsal view, urogomphi present;

-  Bryaxis italicus, antennae ending with a very long bristle;

-  Brachygluta abrupta, antennae without a typical sensory lobe, ninth abdominal segment deeply

excavare; .

- Pselaphus heisei, shape and size of antennae, lengrh of rhe exsertile head organs, very particular comb of serae ar rhe ninth abdominal segment.
The new data confirm that Pselaphid larvae separares wirhin rhe Sraphylinoidea owing to the following combinarion of characreristics: l) mandibles wirhour molar part, 2) mala nor arriculared to the stipes, 3) mandibles not recurved, 4) ligula absent, 5) labrum indisrincr, 6) urogomphi absent or small and immovable, 7) antennae not longer rhan head, 8) ocelli less than six or absent, 9) terga not expanded, 10) antennae sometimes with forked sensory lobe, 11) head sometimes with a pair of exserrile organs.