Homilopsocidea

Introduction

Infraorder Homilopsocidea contains ten families: Bryopsocidae, Calopsocidae, Ectopsocidae, Elipsocidae, Lachesillidae, Mesopsocidae, Peripsocidae, Philotarsidae, and Pseudocaeciliidae, and Trichopscidae.  These families comprise about 90 genera and 1500 species worldwide.

Members of this infraorder are very diverse morphologically and biologically.

Characteristics

Synapomorphies

(from Yoshizawa 2002):

• Female:
• Egg guide extends from the dorsodistal margin of the subgenital plate.
• Dorsal valve of the gonapophyses is swollen dorsally.
  

General Characters

(from Yoshizawa 2002):

• Head:
  • Head usually has a rounded vertex, except sharply pointed in Calopsocidae.
  • Postclypeus is usually well bulged.
  • Epistomal suture with or without well developed internal ridge.
  • Anteclypeus varies.
  • Eyes are usually much larger on males than on females.
  • Ocelli are present and usually clustered on weakly developed tubercle.
  • Mandibles are short, with rounded outer margin (except Calopsocidae with somewhat angled outer margin).
  • Lacinial tip is usually bicuspid.
  • Galea is usually flattened.
  • Labial palpi are rounded.
• Thorax:
  • Prothorax is less bulged dorsally than in other Psocomorpha.
  • Pterothorax is strongly bulged dorsally.
  • Mesothorax has a broad precoxal bridge and narrow trochantin.
  • Metaepisternum has a broad membranous region.
• Wings:
  • Forewing varies in coloration and markings.
  • Posteroproximal corner of forewing is smoothly rounded.
  • Forewing venation is generally of Caecilius-type.
  • Hindwing has a rounded posteroproximal corner.
  • Hindwing vein Sc is faint.
• Male: Genitalia vary; phallosome is complete.
• Female genitalia:
  • Subgenital plate usually has a distal projection extended from dorsal margin.
  • Gonapophyses are usually complete:
    • Dorsal valve is swollen dorsally, usually with a subapical ventral process.

Discussion of Phylogenetic Relationships

Monophyly of Infraorder Homilopsocidea is uncertain.  Morphological data support monophyly based on the synapomorphic characters listed under Characteristics (Yoshizawa 2002).  Molecular data, however, divide the infraorder: one clade contains families Calopsocidae, Philotarsidae, and Psedocaeciliidae, and a series of small clades (sister to Infraorder Caeciliusetae) contain families Ectopsocidae, Lachesillidae, Elipsocidae, and Mesopsocidae (Johnson et al. 2004).  Further work is needed to clarify relationships within the infraorder.

References

Johnson, K. P. & E. L. Mockford. 2003. Molecular systematics of Psocomorpha (Psocoptera). Systematic Entomology 28: 409-40

Johnson, K. P., K. Yoshizawa, and V. S. Smith. 2004. Multiple origins of parasitism in lice. Proceeding of the Royal Society of London B 271: 1771-1776.

Lienhard, C. and C. N Smithers. 2002. Psocoptera (Insecta) World Catalogue and Bibliography. Muséum d'Histoire Naturelle, Geneva, Switzerland.

Mockford, E. L. 1993. North American Psocoptera (Insecta). Gainesville, Florida: Sandhill Crane Press.

Mockford, E. L. 2005. Order Psocoptera: Psocids. Pp. 341-355 in C. A. Triplehorn and n. F. Johnson (eds.) Borror and DeLong's Introduction to the Study of Insects. Belmont, California: Thomson Publishing.

Smithers, C. N. 1996. Psocoptera. Pp. 1-80, 363-372 (Index) in A. Wells (ed.) Zoological Catalogue of Australia. Vol. 26. Psocoptera, Phthiraptera, Thysanoptera. Melbourne: CSIRO Publishing, Australia.

Yoshizawa, K. 2002. Phylogeny and higher classification of suborder Psocomorpha (Insecta: Psocodea:'Psocoptera'). Zoological Journal of the Linnean Society 136: 371-400.